chore(monorepo): update pnpm.catalog.default astro to ^5.16.11 [security]

[renovate]

ℹ️ Note

This PR body was truncated due to platform limits.

This PR contains the following updates:

Package	Change	Age	Confidence
astro (source)	^5.13.5 → ^5.16.11

GitHub Vulnerability Alerts

CVE-2025-61925

Summary

When running Astro in on-demand rendering mode using a adapter such as the node adapter it is possible to maliciously send an X-Forwarded-Host header that is reflected when using the recommended Astro.url property as there is no validation that the value is safe.

Details

Astro reflects the value in X-Forwarded-Host in output when using Astro.url without any validation.

It is common for web servers such as nginx to route requests via the Host header, and forward on other request headers. As such as malicious request can be sent with both a Host header and an X-Forwarded-Host header where the values do not match and the X-Forwarded-Host header is malicious. Astro will then return the malicious value.

This could result in any usages of the Astro.url value in code being manipulated by a request. For example if a user follows guidance and uses Astro.url for a canonical link the canonical link can be manipulated to another site. It is not impossible to imagine that the value could also be used as a login/registration or other form URL as well, resulting in potential redirecting of login credentials to a malicious party.

As this is a per-request attack vector the surface area would only be to the malicious user until one considers that having a caching proxy is a common setup, in which case any page which is cached could persist the malicious value for subsequent users.

Many other frameworks have an allowlist of domains to validate against, or do not have a case where the headers are reflected to avoid such issues.

PoC

• Check out the minimal Astro example found here: https://github.com/Chisnet/minimal_dynamic_astro_server
• nvm use
• yarn run build
• node ./dist/server/entry.mjs
• curl --location 'http://localhost:4321/' --header 'X-Forwarded-Host: www.evil.com' --header 'Host: www.example.com'
• Observe that the response reflects the malicious X-Forwarded-Host header

For the more advanced / dangerous attack vector deploy the application behind a caching proxy, e.g. Cloudflare, set a non-zero cache time, perform the above curl request a few times to establish a cache, then perform the request without the malicious headers and observe that the malicious data is persisted.

Impact

This could affect anyone using Astro in an on-demand/dynamic rendering mode behind a caching proxy.

CVE-2025-64745

Summary

A Reflected Cross-Site Scripting (XSS) vulnerability exists in Astro's development server error pages when the trailingSlash configuration option is used. An attacker can inject arbitrary JavaScript code that executes in the victim's browser context by crafting a malicious URL. While this vulnerability only affects the development server and not production builds, it could be exploited to compromise developer environments through social engineering or malicious links.

Details

Vulnerability Location

https://github.com/withastro/astro/blob/5bc37fd5cade62f753aef66efdf40f982379029a/packages/astro/src/template/4xx.ts#L133-L149

Root Cause

The vulnerability was introduced in commit 536175528 (PR #​12994) , as part of a feature to "redirect trailing slashes on on-demand rendered pages." The feature added a helpful 404 error page in development mode to alert developers of trailing slash mismatches.

Issue: The corrected variable, which is derived from the user-controlled pathname parameter, is directly interpolated into the HTML without proper escaping. While the pathname variable itself is escaped elsewhere in the same file (line 114: escape(pathname)), the corrected variable is not sanitized before being inserted into both the href attribute and the link text.

Attack Vector

When a developer has configured trailingSlash to 'always' or 'never' and visits a URL with a mismatched trailing slash, the development server returns a 404 page containing the vulnerable template. An attacker can craft a URL with JavaScript payloads that will be executed when the page is rendered.

PoC

Local Testing (localhost)

Basic vulnerability verification in local development environment

Show details

astro.config.mjs:

import { defineConfig } from 'astro/config';

export default defineConfig({
  trailingSlash: 'never', // or 'always'
  server: {
    port: 3000,
    host: true
  }
});

package.json:

{
  "name": "astro-xss-poc-victim",
  "version": "0.1.0",
  "scripts": {
    "dev": "astro dev"
  },
  "dependencies": {
    "astro": "5.15.5"
  }
}

Start the development server:

npm install
npm run dev

Access the following malicious URL depending on your configuration:

For trailingSlash: 'never' (requires trailing slash):

http://localhost:3000/"></code><script>alert(document.domain)</script><!--/

For trailingSlash: 'always' (no trailing slash):

http://localhost:3000/"></code><script>alert(document.domain)</script><!--

When accessing the malicious URL:

1. The development server returns a 404 page due to trailing slash mismatch
2. The JavaScript payload (alert(document.domain)) executes in the browser
3. An alert dialog appears, demonstrating arbitrary code execution

Remote Testing (ngrok)

Reproduce realistic attack scenario via external malicious link

Show details

Prerequisites: ngrok account and authtoken configured (ngrok config add-authtoken <key>)

Setup and Execution:

#!/bin/bash
set -e

mkdir -p logs

npm i
npm run dev > ./logs/victim.log 2>&1 &

ngrok http 3000 > ./logs/ngrok.log 2>&1 &

sleep 3

NGROK_URL=$(curl -s http://localhost:4040/api/tunnels | grep -o '"public_url":"https://[^"]*' | head -1 | cut -d'"' -f4)
echo ""
echo "=== Attack URLs ==="
echo ""
echo "For trailingSlash: 'never' (requires trailing slash):"
echo "${NGROK_URL}/\"></code><script>alert(document.domain)</script><!--/"
echo ""
echo "For trailingSlash: 'always' (no trailing slash):"
echo "${NGROK_URL}/\"></code><script>alert(document.domain)</script><!--"
echo ""
wait

When a remote user accesses either of the generated attack URLs:

1. The request is tunneled through ngrok to the local development server
2. The development server returns a 404 page due to trailing slash mismatch
3. The JavaScript payload (alert(document.domain)) executes in the user's browser

Both URL patterns work depending on your trailingSlash configuration ('never' or 'always').

Impact

This only affects the development server. Risk depends on how and where the dev server is exposed.

Security impact

• Developer environment compromise: Visiting a crafted URL can run arbitrary JS in the developer's browser.
• Session hijacking: Active developer sessions can be stolen if services are open in the browser.
• Local resource access: JS may probe localhost endpoints or dev tools depending on browser policies.
• Supply-chain risk: Malicious packages or CI that start dev servers can widen exposure.

Attack scenarios

• Social engineering: Malicious link sent to a developer triggers the XSS when opened.
• Malicious documentation: Attack URLs embedded in issues, PRs, chat, or docs.
• Dependency/CI abuse: Packages or automation that spawn public dev servers expose many targets.

CVE-2025-64525

Summary

In impacted versions of Astro using on-demand rendering, request headers x-forwarded-proto and x-forwarded-port are insecurely used, without sanitization, to build the URL. This has several consequences the most important of which are:

• Middleware-based protected route bypass (only via x-forwarded-proto)
• DoS via cache poisoning (if a CDN is present)
• SSRF (only via x-forwarded-proto)
• URL pollution (potential SXSS, if a CDN is present)
• WAF bypass

Details

The x-forwarded-proto and x-forwarded-port headers are used without sanitization in two parts of the Astro server code. The most important is in the createRequest() function. Any configuration, including the default one, is affected:

https://github.com/withastro/astro/blob/970ac0f51172e1e6bff4440516a851e725ac3097/packages/astro/src/core/app/node.ts#L97
https://github.com/withastro/astro/blob/970ac0f51172e1e6bff4440516a851e725ac3097/packages/astro/src/core/app/node.ts#L121

These header values are then used directly to construct URLs.

By injecting a payload at the protocol level during URL creation (via the x-forwarded-proto header), the entire URL can be rewritten, including the host, port and path, and then pass the rest of the URL, the real hostname and path, as a query so that it doesn't affect (re)routing.

If the following header value is injected when requesting the path /ssr:

x-forwarded-proto: https://www.malicious-url.com/?tank=

The complete URL that will be created is: https://www.malicious-url.com/?tank=://localhost/ssr

As a reminder, URLs are created like this:

url = new URL(`${protocol}://${hostnamePort}${req.url}`);

The value is injected at the beginning of the string (${protocol}), and ends with a query ?tank= whose value is the rest of the string, ://${hostnamePort}${req.url}.

This way there is control over the routing without affecting the path, and the URL can be manipulated arbitrarily. This behavior can be exploited in various ways, as will be seen in the PoC section.

The same logic applies to x-forwarded-port, with a few differences.

Note

The createRequest function is called every time a non-static page is requested. Therefore, all non-static pages are exploitable for reproducing the attack.

PoC

The PoC will be tested with a minimal repository:

• Latest Astro version at the time (2.16.0)
• The Node adapter
• Two simple pages, one SSR (/ssr), the other simulating an admin page (/admin) protected by a middleware
• A middleware example copied and pasted from the official Astro documentation to protect the admin page based on the path

Download the PoC repository

Middleware-based protected route bypass - x-forwarded-proto only

The middleware has been configured to protect the /admin route based on the official documentation:

// src/middleware.ts
import { defineMiddleware } from "astro/middleware";

export const onRequest = defineMiddleware(async (context, next) => {
  const isAuthed = false; // auth logic
  if (context.url.pathname === "/admin" && !isAuthed) {
    return context.redirect("/");
  }
  return next();
});

1. When tryint to access /admin the attacker is naturally redirected :

   curl -i http://localhost:4321/admin

   

2. The attackr can bypass the middleware path check using a malicious header value:

   curl -i -H "x-forwarded-proto: x:admin?" http://localhost:4321/admin

   

How ​​is this possible?

Here, with the payload x:admin?, the attacker can use the URL API parser to their advantage:

• x: is considered the protocol
• Since there is no //, the parser considers there to be no authority, and everything before the ? character is therefore considered part of the path: admin

During a path-based middleware check, the path value begins with a /: context.url.pathname === "/admin". However, this is not the case with this payload; context.url.pathname === "admin", the absence of a slash satisfies both the middleware check and the router and consequently allows us to bypass the protection and access the page.

SSRF

As seen, the request URL is built from untrusted input via the x-forwarded-protocol header, if it turns out that this URL is subsequently used to perform external network calls, for an API for example, this allows an attacker to supply a malicious URL that the server will fetch, resulting in server-side request forgery (SSRF).

Example of code reusing the "origin" URL, concatenating it to the API endpoint :

DoS via cache poisoning

If a CDN is present, it is possible to force the caching of bad pages/resources, or 404 pages on the application routes, rendering the application unusable.

A 404 cab be forced, causing an error on the /ssr page like this : curl -i -H "x-forwarded-proto: https://localhost/vulnerable?" http://localhost:4321/ssr

Same logic applies to x-forwarded-port : curl -i -H "x-forwarded-port: /vulnerable?" http://localhost:4321/ssr

How ​​is this possible?

The router sees the request for the path /vulnerable, which does not exist, and therefore returns a 404, while the potential CDN sees /ssr and can then cache the 404 response, consequently serving it to all users requesting the path /ssr.

URL pollution

The exploitability of the following is also contingent on the presence of a CDN, and is therefore cache poisoning.

If the value of request.url is used to create links within the page, this can lead to Stored XSS with x-forwarded-proto and the following value:

x-forwarded-proto: javascript:alert(document.cookie)//

results in the following URL object:

It is also possible to inject any link, always, if the value of request.url is used on the server side to create links.

x-forwarded-proto: https://www.malicious-site.com/bad?

The attacker is more limited with x-forwarded-port

If the value of request.url is used to create links within the page, this can lead to broken links, with the header and the following value:

X-Forwarded-Port: /nope?

Example of an Astro website:

WAF bypass

For this section, Astro invites users to read previous research on the React-Router/Remix framework, in the section "Exploitation - WAF bypass and escalations". This research deals with a similar case, the difference being that the vulnerable header was x-forwarded-host in their case:

https://zhero-web-sec.github.io/research-and-things/react-router-and-the-remixed-path

Note: A section addressing DoS attacks via cache poisoning using the same vector was also included there.

CVE-2025-61925 complete bypass

It is possible to completely bypass the vulnerability patch related to the X-Forwarded-Host header.

By sending x-forwarded-host with an empty value, the forwardedHostname variable is assigned an empty string. Then, during the subsequent check, the condition fails because forwardedHostname returns false, its value being an empty string:

if (forwardedHostname && !App.validateForwardedHost(...))

Consequently, the implemented check is bypassed. From this point on, since the request has no host (its value being an empty string), the path value is retrieved by the URL parser to set it as the host. This is because the http/https schemes are considered special schemes by the WHATWG URL Standard Specification, requiring an authority state.

From there, the following request on the example SSR application (astro repo) yields an SSRF:

empty x-forwarded-host + the target host in the path

Credits

• Allam Rachid (zhero;)
• Allam Yasser (inzo)

CVE-2025-64757

Summary

A vulnerability has been identified in the Astro framework's development server that allows arbitrary local file read access through the image optimization endpoint. The vulnerability affects Astro development environments and allows remote attackers to read any image file accessible to the Node.js process on the host system.

Details

• Title: Arbitrary Local File Read in Astro Development Image Endpoint
• Type: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
• Component: /packages/astro/src/assets/endpoint/node.ts
• Affected Versions: Astro v5.x development builds (confirmed v5.13.3)
• Attack Vector: Network (HTTP GET request)
• Authentication Required: None

The vulnerability exists in the Node.js image endpoint handler used during development mode. The endpoint accepts an href parameter that specifies the path to an image file. In development mode, this parameter is processed without adequate path validation, allowing attackers to specify absolute file paths.

Vulnerable Code Location: packages/astro/src/assets/endpoint/node.ts

// Vulnerable code in development mode
if (import.meta.env.DEV) {
    fileUrl = pathToFileURL(removeQueryString(replaceFileSystemReferences(src)));
} else {
    // Production has proper path validation
    // ... security checks omitted in dev mode
}

The development branch bypasses the security checks that exist in the production code path, which validates that file paths are within the allowed assets directory.

PoC

Attack Prerequisites

1. Astro development server must be running (astro dev)
2. The /_image endpoint must be accessible to the attacker
3. Target image files must be readable by the Node.js process

Exploit Steps

1. Start Astro Development Server:

   astro dev  # Typically runs on http://localhost:4321

2. Craft Malicious Request:

   GET /_image?href=/[ABSOLUTE_PATH_TO_IMAGE]&w=100&h=100&f=png HTTP/1.1
   Host: localhost:4321

3. Example Attack:

   curl "http://localhost:4321/_image?href=/%2FSystem%2FLibrary%2FImage%20Capture%2FAutomatic%20Tasks%2FMakePDF.app%2FContents%2FResources%2F0blank.jpg&w=100&h=100&f=png" -o stolen.png

Demonstration Results

Test Environment: macOS with Astro v5.13.3

Successful Exploitation:

• Target: /System/Library/Image Capture/Automatic Tasks/MakePDF.app/Contents/Resources/0blank.jpg
• Response: HTTP 200 OK, Content-Type: image/png
• Exfiltration: 303 bytes (100x100 PNG)
• File Created: stolen-image.png containing processed system image

Attack Payload:

http://localhost:4321/_image?href=/%2FSystem%2FLibrary%2FImage%20Capture%2FAutomatic%20Tasks%2FMakePDF.app%2FContents%2FResources%2F0blank.jpg&w=100&h=100&f=png

Server Response:

Status: 200 OK
Content-Type: image/png
Content-Length: 303

Impact

Confidentiality Impact: HIGH

• Scope: Any image file readable by the Node.js process
• Exfiltration Method: Complete file contents via HTTP response (transformed to PNG)

Integrity Impact: NONE

• The vulnerability only allows reading files, not modification

Availability Impact: NONE

• No direct impact on system availability
• Potential for resource exhaustion through repeated large image requests

Affected Components

Primary Component

• File: packages/astro/src/assets/endpoint/node.ts
• Function: loadLocalImage()
• Lines: Development mode branch (~25-35)

Secondary Components

• File: packages/astro/src/assets/endpoint/generic.ts
• Impact: Uses different code path, not directly vulnerable
• Note: Implements proper remote allowlist validation

CVE-2025-64764

Summary

After some research it appears that it is possible to obtain a reflected XSS when the server islands feature is used in the targeted application, regardless of what was intended by the component template(s).

Details

Server islands run in their own isolated context outside of the page request and use the following pattern path to hydrate the page: /_server-islands/[name]. These paths can be called via GET or POST and use three parameters:

• e: component to export
• p: the transmitted properties, encrypted
• s: for the slots

Slots are placeholders for external HTML content, and therefore allow, by default, the injection of code if the component template supports it, nothing exceptional in principle, just a feature.

This is where it becomes problematic: it is possible, independently of the component template used, even if it is completely empty, to inject a slot containing an XSS payload, whose parent is a tag whose name is is the absolute path of the island file. Enabling reflected XSS on any application, regardless of the component templates used, provided that the server islands is used at least once.

How ?

By default, when a call is made to the endpoint /_server-islands/[name], the value of the parameter e is default, pointing to a function exported by the component's module.

Upon further investigation, we find that two other values ​​are possible for the component export (param e) in a typical configuration: url and file. file returns a string value corresponding to the absolute path of the island file. Since the value is of type string, it fulfills the following condition and leads to this code block:

An entire template is created, completely independently, and then returned:

• the absolute path name is sanitized and then injected as the tag name
• childSlots, the value provided to the s parameter, is injected as a child

All of this is done using markHTMLString. This allows the injection of any XSS payload, even if the component template intended by the application is initially empty or does not provide for the use of slots.

Proof of concept

For our Proof of Concept (PoC), we will use a minimal repository:

• Latest Astro version at the time (5.15.6)
• Use of Island servers, with a completely empty component, to demonstrate what we explained previously

Download the PoC repository

Access the following URL and note the opening of the popup, demonstrating the reflected XSS:

http://localhost:4321/_server-islands/ServerTime?e=file&p=&s={%22zhero%22:%22%3Cimg%20src=x%20onerror=alert(0)%3E%22}

The value of the parameter s must be in JSON format and the payload must be injected at the value level, not the key level :

Despite the initial template being empty, it is created because the value of the URL parameter e is set to file, as explained earlier. The parent tag is the name of the component's internal route, and its child is the value of the key "zhero" (the name doesn't matter) of the URL parameter s.

Credits

• Allam Rachid (zhero;)
• Allam Yasser (inzo)

CVE-2025-64765

A mismatch exists between how Astro normalizes request paths for routing/rendering and how the application’s middleware reads the path for validation checks. Astro internally applies decodeURI() to determine which route to render, while the middleware uses context.url.pathname without applying the same normalization (decodeURI).

This discrepancy may allow attackers to reach protected routes (e.g., /admin) using encoded path variants that pass routing but bypass validation checks.

https://github.com/withastro/astro/blob/ebc4b1cde82c76076d5d673b5b70f94be2c066f3/packages/astro/src/vite-plugin-astro-server/request.ts#L40-L44

/** The main logic to route dev server requests to pages in Astro. */
export async function handleRequest({
    pipeline,
    routesList,
    controller,
    incomingRequest,
    incomingResponse,
}: HandleRequest) {
    const { config, loader } = pipeline;
    const origin = `${loader.isHttps() ? 'https' : 'http'}://${
        incomingRequest.headers[':authority'] ?? incomingRequest.headers.host
    }`;

    const url = new URL(origin + incomingRequest.url);
    let pathname: string;
    if (config.trailingSlash === 'never' && !incomingRequest.url) {
        pathname = '';
    } else {
        // We already have a middleware that checks if there's an incoming URL that has invalid URI, so it's safe
        // to not handle the error: packages/astro/src/vite-plugin-astro-server/base.ts
        pathname = decodeURI(url.pathname); // here this url is for routing/rendering
    }

    // Add config.base back to url before passing it to SSR
    url.pathname = removeTrailingForwardSlash(config.base) + url.pathname; // this is used for middleware context

Consider an application having the following middleware code:

import { defineMiddleware } from "astro/middleware";

export const onRequest = defineMiddleware(async (context, next) => {
  const isAuthed = false;  // simulate no auth
  if (context.url.pathname === "/admin" && !isAuthed) {
    return context.redirect("/");
  }
  return next();
});

context.url.pathname is validated , if it's equal to /admin the isAuthed property must be true for the next() method to be called. The same example can be found in the official docs https://docs.astro.build/en/guides/authentication/

context.url.pathname returns the raw version which is /%61admin while pathname which is used for routing/rendering /admin, this creates a path normalization mismatch.

By sending the following request, it's possible to bypass the middleware check

GET /%61dmin HTTP/1.1
Host: localhost:3000

Remediation

Ensure middleware context has the same normalized pathname value that Astro uses internally, because any difference could allow it to bypass such checks. In short maybe something like this

        pathname = decodeURI(url.pathname);
    }

    // Add config.base back to url before passing it to SSR
-    url.pathname = removeTrailingForwardSlash(config.base) + url.pathname;
+    url.pathname = removeTrailingForwardSlash(config.base) + decodeURI(url.pathname);

Thank you, let @​Sudistark know if any more info is needed. Happy to help :)

CVE-2025-65019

Summary
A Cross-Site Scripting (XSS) vulnerability exists in Astro when using the @​astrojs/cloudflare adapter with output: 'server'. The built-in image optimization endpoint (/_image) uses isRemoteAllowed() from Astro’s internal helpers, which unconditionally allows data: URLs. When the endpoint receives a valid data: URL pointing to a malicious SVG containing JavaScript, and the Cloudflare-specific implementation performs a 302 redirect back to the original data: URL, the browser directly executes the embedded JavaScript. This completely bypasses any domain allow-listing (image.domains / image.remotePatterns) and typical Content Security Policy mitigations.

Affected Versions

• @astrojs/cloudflare ≤ 12.6.10 (and likely all previous versions)
• Astro ≥ 4.x when used with output: 'server' and the Cloudflare adapter

Root Cause – Vulnerable Code
File: node_modules/@​astrojs/internal-helpers/src/remote.ts

export function isRemoteAllowed(src: string, ...): boolean {
  if (!URL.canParse(src)) {
    return false;
  }
  const url = new URL(src);

  // Data URLs are always allowed 
  if (url.protocol === 'data:') {
    return true;
  }

  // Non-http(s) protocols are never allowed
  if (!['http:', 'https:'].includes(url.protocol)) {
    return false;
  }
  // ... further http/https allow-list checks
}

In the Cloudflare adapter, the /_image endpoint contains logic similar to:

	const href = ctx.url.searchParams.get('href');
	if (!href) {
		// return error 
	}

	if (isRemotePath(href)) {
		if (isRemoteAllowed(href, imageConfig) === false) {
			// return error
		} else {
            //redirect to return the image 
			return Response.redirect(href, 302);
		}
	}

Because data: URLs are considered “allowed”, a request such as:
https://example.com/_image?href=data:image/svg+xml;base64,PHN2Zy... (base64-encoded malicious SVG)

triggers a 302 redirect directly to the data: URL, causing the browser to render and execute the malicious JavaScript inside the SVG.

Proof of Concept (PoC)

1. Create a minimal Astro project with Cloudflare adapter (output: 'server').
2. Deploy to Cloudflare Pages or Workers.
3. Request the image endpoint with the following payload:

https://yoursite.com/_image?href=data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjxzY3JpcHQ+YWxlcnQoJ3pvbWFzZWMnKTwvc2NyaXB0Pjwvc3ZnPg==

(Base64 decodes to: <svg xmlns="http://www.w3.org/2000/svg"><script>alert('zomasec')</script></svg>)

4. The endpoint returns a 302 redirect to the data: URL → browser executes the <script> → alert() fires.

Impact

• Reflected/Strored XSS (depending on application usage)
• Session hijacking (access to cookies, localStorage, etc.)
• Account takeover when combined with CSRF
• Data exfiltration to attacker-controlled servers
• Bypasses image.domains / image.remotePatterns configuration entirely

Safe vs Vulnerable Behavior
Other Astro adapters (Node, Vercel, etc.) typically proxy and rasterize SVGs, stripping JavaScript. The Cloudflare adapter currently redirects to remote resources (including data: URLs), making it uniquely vulnerable.

References

• Vulnerable function: https://github.com/withastro/astro/blob/main/packages/internal-helpers/src/remote.ts
• Similar data: URL bypass in WordPress: CVE-2025-2575

CVE-2025-66202

Authentication Bypass via Double URL Encoding in Astro

Bypass for CVE-2025-64765 / GHSA-ggxq-hp9w-j794

---

Summary

A double URL encoding bypass allows any unauthenticated attacker to bypass path-based authentication checks in Astro middleware, granting unauthorized access to protected routes. While the original CVE-2025-64765 (single URL encoding) was fixed in v5.15.8, the fix is insufficient as it only decodes once. By using double-encoded URLs like /%2561dmin instead of /%61dmin, attackers can still bypass authentication and access protected resources such as /admin, /api/internal, or any route protected by middleware pathname checks.

Fix

A more secure fix is just decoding once, then if the request has a %xx format, return a 400 error by using something like :

if (containsEncodedCharacters(pathname)) {
            // Multi-level encoding detected - reject request
            return new Response(
                'Bad Request: Multi-level URL encoding is not allowed',
                {
                    status: 400,
                    headers: { 'Content-Type': 'text/plain' }
                }
            );
        }

---

Release Notes

withastro/astro (astro)

v5.16.11

Compare Source

Patch Changes

• #​15017 9e7a3c8 Thanks @​ixchio! - Fixes CSS double-bundling when the same CSS file is imported in both a page's frontmatter and a component's script tag

• #​15225 6fe62e1 Thanks @​ematipico! - Updates to the latest version of devalue

v5.16.10

Compare Source

Patch Changes

• 2fa19c4 - Improved error handling in the rendering phase

  Added defensive validation in App.render() and #renderError() to provide a descriptive error message when a route module doesn't have a valid page function.

• #​15199 d8e64ef Thanks @​ArmandPhilippot! - Fixes the links to Astro Docs so that they match the current docs structure.

• #​15169 b803d8b Thanks @​rururux! - fix: fix image 500 error when moving dist directory in standalone Node

• #​14622 9b35c62 Thanks @​aprici7y! - Fixes CSS url() references to public assets returning 404 in dev mode when base path is configured

• #​15219 43df4ce Thanks @​matthewp! - Upgrades the diff package to v8

v5.16.9

Compare Source

Patch Changes

• #​15174 37ab65a Thanks @​florian-lefebvre! - Adds Google Icons to built-in font providers

  To start using it, access it on fontProviders:

  import { defineConfig, fontProviders } from 'astro/config';
  
  export default defineConfig({
    experimental: {
      fonts: [
        {
          name: 'Material Symbols Outlined',
          provider: fontProviders.googleicons(),
          cssVariable: '--font-material',
        },
      ],
    },
  });

• #​15150 a77c4f4 Thanks @​matthewp! - Fixes hydration for framework components inside MDX when using Astro.slots.render()

  Previously, when multiple framework components with client:* directives were passed as named slots to an Astro component in MDX, only the first slot would hydrate correctly. Subsequent slots would render their HTML but fail to include the necessary hydration scripts.

• #​15130 9b726c4 Thanks @​florian-lefebvre! - BREAKING CHANGE to the experimental Fonts API only

  Changes how font providers are implemented with updates to the FontProvider type

  This is an implementation detail that changes how font providers are created. This process allows Astro to take more control rather than relying directly on unifont types. All of Astro's built-in font providers have been updated to reflect this new type, and can be configured as before. However, using third-party unifont providers that rely on unifont types will require an update to your project code.

  Previously, an Astro FontProvider was made of a config and a runtime part. It relied directly on unifont types, which allowed a simple configuration for third-party unifont providers, but also coupled Astro's implementation to unifont, which was limiting.

  Astro's font provider implementation is now only made of a config part with dedicated hooks. This allows for the separation of config and runtime, but requires you to create a font provider object in order to use custom font providers (e.g. third-party unifont providers, or private font registeries).

What should I do?

If you were using a 3rd-party unifont font provider, you will now need to write an Astro FontProvider using it under the hood. For example:

// astro.config.ts
import { defineConfig } from "astro/config";
import { acmeProvider, type AcmeOptions } from '@​acme/unifont-provider'
+import type { FontProvider } from "astro";
+import type { InitializedProvider } from 'unifont';

+function acme(config?: AcmeOptions): FontProvider {
+	const provider = acmeProvider(config);
+	let initializedProvider: InitializedProvider | undefined;
+	return {
+		name: provider._name,
+		config,
+		async init(context) {
+			initializedProvider = await provider(context);
+		},
+		async resolveFont({ familyName, ...rest }) {
+			return await initializedProvider?.resolveFont(familyName, rest);
+		},
+		async listFonts() {
+			return await initializedProvider?.listFonts?.();
+		},
+	};
+}

export default defineConfig({
    experimental: {
        fonts: [{
-            provider: acmeProvider({ /* ... */ }),
+            provider: acme({ /* ... */ }),
            name: "Material Symbols Outlined",
            cssVariable: "--font-material"
        }]
    }
});

• #​15147 9cd5b87 Thanks @​matthewp! - Fixes scripts in components not rendering when a sibling <Fragment slot="..."> exists but is unused

v5.16.8

Compare Source

Patch Changes

• #​15124 81db3c0 Thanks @​leonace924! - Fixes an issue where requests with query parameters to the base path would return a 404 if trailingSlash was not 'ignore' in development

• #​15152 39ee41f Thanks @​rururux! - Fixes a case where context.cookies.set() would be overriden when setting cookies via response headers in development

• #​15140 6f6f8f8 Thanks @​cameronraysmith! - Fixes esbuild warning due to dead code in assets virtual module

• #​15127 2cff904 Thanks @​Princesseuh! - Updates "Unsupported page types found" error to only appear in more realistic cases

• #​15149 34f84c2 Thanks @​rahuld109! - Skips "Use the Image component" audit warning for images inside framework components (React, Vue, Svelte, etc.)

v5.16.7

Compare Source

Patch Changes

• #​15122 b137946 Thanks @​florian-lefebvre! - Improves JSDoc annotations for AstroGlobal, AstroSharedContext and APIContext types

• #​15123 3f58fa2 Thanks @​43081j! - Improves rendering performance by grouping render chunks when emitting from async iterables to avoid encoding costs

• #​14954 7bec4bd Thanks @​volpeon! - Fixes remote images Etag header handling by disabling internal cache

• #​15052 b2bcd5a Thanks @​Princesseuh! - Fixes images not working in development when using setups with port forwarding

• #​15028 87b19b8 Thanks @​Princesseuh! - Fixes certain aliases not working when using images in JSON files with the content layer

• #​15118 cfa382b Thanks @​florian-lefebvre! - BREAKING CHANGE to the experimental Fonts API only

  Removes the defineAstroFontProvider() type helper.

  If you are building a custom font provider, remove any occurrence of defineAstroFontProvider() and use the FontProvider type instead:

  -import { defineAstroFontProvider } from 'astro/config';
  
  -export function myProvider() {
  -    return defineAstroFontProvider({
  -        entrypoint: new URL('./implementation.js', import.meta.url)
  -    });
  -};
  
  +import type { FontProvider } from 'astro';
  
  +export function myProvider(): FontProvider {
  +    return {
  +        entrypoint: new URL('./implementation.js', import.meta.url)
  +    },
  +}

• #​15055 4e28db8 Thanks @​delucis! - Reduces Astro’s install size by around 8 MB

• #​15088 a19140f Thanks @​martrapp! - Enables the ClientRouter to preserve the original hash part of the target URL during server side redirects.

• #​15117 b1e8e32 Thanks @​florian-lefebvre! - BREAKING CHANGE to the experimental Fonts API only

  Changes the font format downloaded by default when using the experimental Fonts API. Additionally, adds a new formats configuration option to specify which font formats to download.

  Previously, Astro was opinionated about which font sources would be kept for usage, mainly keeping woff2 and woff files.

  You can now specify what font formats should be downloaded (if available). Only woff2 files are downloaded by default.

What should I do?

If you were previously relying on Astro downloading the woff format, you will now need to specify this explicitly with the new formats configuration option. Additionally, you may also specify any additional file formats to download if available:

// astro.config.mjs
import { defineConfig, fontProviders } from 'astro/config'

export default defineConfig({
    experimental: {
        fonts: [{
            name: 'Roboto',
            cssVariable: '--font-roboto',
            provider: fontProviders.google(),
+            formats: ['woff2', 'woff', 'otf']
        }]
    }
})

• #​15034 8115752 Thanks @​florian-lefebvre! - Fixes a vite warning log during builds when using npm

v5.16.6

Compare Source

Patch Changes

• #​14982 6849e38 Thanks @​Princesseuh! - Fixes images outside the project directory not working when using astro:assets in development mode

• #​14987 9dd9fca Thanks @​Princesseuh! - Fixes SVGs not working in dev mode when using the passthrough image service

• #​15014 a178422 Thanks @​delucis! - Adds support for extending the type of the props accepted by Astro’s <Image> component, <Picture> component, and getImage() API.

v5.16.5

Compare Source

Patch Changes

• #​14985 c016f10 Thanks @​florian-lefebvre! - Fixes a case where JSDoc annotations wouldn't show for fonts related APIs in the Astro config

• #​14973 ed7cc2f Thanks @​amankumarpandeyin! - Fixes performance regression and OOM errors when building medium-sized blogs with many content entries. Replaced O(n²) object spread pattern with direct mutation in generateLookupMap.

• #​14958 70eb542 Thanks @​ascorbic! - Gives a helpful error message if a user sets output: "hybrid" in their Astro config.

  The option was removed in Astro 5, but lots of content online still references it, and LLMs often suggest it. It's not always clear that the replacement is output: "static", rather than output: "server". This change adds a helpful error message to guide humans and robots.

• #​14901 ef53716 Thanks @​Darknab! - Updates the glob() loader to log a warning when duplicated IDs are detected

• Updated dependencies [d8305f8]:

  • @​astrojs/markdown-remark@​6.3.10

v5.16.4

Compare Source

Patch Changes

• #​14940 2cf79c2 Thanks @​ematipico! - Fixes a bug where Astro didn't properly combine CSP resources from the csp configuration with those added using the runtime API (Astro.csp.insertDirective()) to form grammatically correct CSP headers

  Now Astro correctly deduplicate CSP resources. For example, if you have a global resource in the configuration file, and then you add a
  a new one using the runtime APIs.

v5.16.3

Compare Source

Patch Changes

• #​14889 4bceeb0 Thanks @​florian-lefebvre! - Fixes actions types when using specific TypeScript configurations

• #​14929 e0f277d Thanks @​matthewp! - Fixes authentication bypass via double URL encoding in middleware

  Prevents attackers from bypassing path-based authentication checks using multi-level URL encoding (e.g., /%2561dmin instead of /%61dmin). Pathnames are now validated after decoding to ensure no additional encoding remains.

v5.16.2

Compare Source

Patch Changes

• #​14876 b43dc7f Thanks @​florian-lefebvre! - Fixes a vite warning log during builds when using npm

• #​14884 10273e0 Thanks @​florian-lefebvre! - Fixes a case where setting the status of a page to 404 in ssr would show an empty page (or 404.astro page if provided) instead of using the current page

v5.16.1

Compare Source

Patch Changes

• #​14769 b43ee71 Thanks @​adriandlam! - Fixes an unhandled rejection issue when using Astro with Vercel Workflow DevKit

• #​14761 345eb22 Thanks @​ooga! - Updates button attributes types to allow command and commandfor

• #​14866 65e214b Thanks @​GameRoMan! - Fixes Astro.glob to be correctly marked as deprecated

• #​14894 1ad9a5b Thanks @​delucis! - Fixes support for Astro component rendering in Vitest test suites using a “client” environment such as happy-dom or jsdom

• #​14782 abed929 Thanks @​florian-lefebvre! - Improves syncing

v5.16.0

Compare Source

Minor Changes

• #​13880 1a2ed01 Thanks @​azat-io! - Adds experimental SVGO optimization support for SVG assets

  Astro now supports automatic SVG optimization using SVGO during build time. This experimental feature helps reduce SVG file sizes while mai

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Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	@​nx/​esbuild@​21.5.3
	@​storm-software/​tsdoc@​0.13.74
	@​opentelemetry/​otlp-grpc-exporter-base@​0.200.0
	@​ltd/​j-toml@​1.38.0
	@​ls-lint/​ls-lint@​2.3.1
	@​microsoft/​tsdoc-config@​0.17.1
	@​microsoft/​tsdoc@​0.15.1
	@​opentelemetry/​otlp-exporter-base@​0.200.0
	@​rollup/​plugin-node-resolve@​16.0.1
	@​opentelemetry/​resources@​2.0.1
	@​rollup/​plugin-commonjs@​28.0.6
	@​microsoft/​api-extractor@​7.52.11
	@​microsoft/​api-extractor@​7.52.13
	@​nuxt/​schema@​4.1.2
	@​nuxt/​kit@​4.1.2
	@​opentelemetry/​api-logs@​0.200.0
	@​nx/​workspace@​21.5.3
	@​opentelemetry/​semantic-conventions@​1.36.0
	@​nx/​jest@​21.5.3
	@​nx/​eslint-plugin@​21.5.3
	@​nx/​devkit@​21.5.3
	@​nx/​react@​21.5.3
	@​nx/​js@​21.5.3
	@​nx/​plugin@​21.5.3
	@​opentelemetry/​exporter-logs-otlp-http@​0.200.0
	@​opentelemetry/​sdk-logs@​0.200.0

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