GHSA-9X9C-GHC5-JHW9

Vulnerability from github – Published: 2025-08-15 16:52 – Updated: 2025-08-15 20:55
VLAI?
Summary
@astrojs/node's trailing slash handling causes open redirect issue
Details

Summary

Following https://github.com/withastro/astro/security/advisories/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

  1. Create a new minimal Astro project (astro@5.12.8)
  2. Configure it to use the Node adapter (@astrojs/node@9.4.0) and force trailing slashes: ```js // astro.config.mjs import { defineConfig } from 'astro/config'; import node from '@astrojs/node';

export default defineConfig({ trailingSlash: 'always', adapter: node({ mode: 'standalone' }), }); `` 3. Build the site by runningastro build. 4. Run the server, e.g. withastro preview. 5. Append//astro.build/press` to the preview URL, e.g. http://localhost:4321//astro.build/press 6. The site will redirect to the external Astro Build origin.

Example reproduction

  1. Open this StackBlitz reproduction.
  2. Open the preview in a separate window so the StackBlitz embed doesn't cause security errors.
  3. Append //astro.build/press to the preview URL, e.g. https://x.local-corp.webcontainer.io//astro.build/press.
  4. 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.

Severity ?
5.5 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:P
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 9.4.0"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@astrojs/node"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "9.4.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-55207"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-601"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-08-15T16:52:48Z",
    "nvd_published_at": "2025-08-15T16:15:30Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nFollowing https://github.com/withastro/astro/security/advisories/GHSA-cq8c-xv66-36gw, there\u0027s still an Open Redirect vulnerability in a subset of Astro deployment scenarios.\n\n### Details\n\nAstro 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`.\n\n### Proof of Concept\n\n1. Create a new minimal Astro project (`astro@5.12.8`)\n2. Configure it to use the Node adapter (`@astrojs/node@9.4.0`) and force trailing slashes:\n   ```js\n   // astro.config.mjs\n   import { defineConfig } from \u0027astro/config\u0027;\n   import node from \u0027@astrojs/node\u0027;\n   \n   export default defineConfig({\n     trailingSlash: \u0027always\u0027,\n     adapter: node({ mode: \u0027standalone\u0027 }),\n   });\n   ```\n3. Build the site by running `astro build`.\n4. Run the server, e.g. with `astro preview`.\n5. Append `//astro.build/press` to the preview URL, e.g. \u003chttp://localhost:4321//astro.build/press\u003e\n6. The site will redirect to the external Astro Build origin.\n\n#### Example reproduction\n\n1. Open [this StackBlitz reproduction](https://stackblitz.com/edit/github-4fvpfhcz-nyfj2mbf).\n2. Open the preview in a separate window so the StackBlitz embed doesn\u0027t cause security errors.\n3. Append `//astro.build/press` to the preview URL, e.g. `https://x.local-corp.webcontainer.io//astro.build/press`.\n4. See it redirect to the external Astro Build origin.\n\n### Impact\n\nThis 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.\n\nNo authentication is required to exploit this vulnerability. Any unauthenticated user can trigger the redirect by clicking a malicious link.",
  "id": "GHSA-9x9c-ghc5-jhw9",
  "modified": "2025-08-15T20:55:55Z",
  "published": "2025-08-15T16:52:48Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/withastro/astro/security/advisories/GHSA-9x9c-ghc5-jhw9"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-55207"
    },
    {
      "type": "WEB",
      "url": "https://github.com/withastro/astro/commit/5fc3c599cacb0172cc7d8e1202a5f2e8685d7ef2"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/withastro/astro"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:P",
      "type": "CVSS_V4"
    }
  ],
  "summary": "@astrojs/node\u0027s trailing slash handling causes open redirect issue"
}


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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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