CVE-2026-41321: @astrojs/cloudflare Cloudflare Has SSRF Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-88gm-j2wx-58h6",
  "modified" : "2026-04-27T16:42:19Z",
  "published" : "2026-04-23T21:52:03Z",
  "aliases" : [ "CVE-2026-41321" ],
  "summary" : "Cloudflare has SSRF via redirect following through its image-binding-transform endpoint (incomplete fix for GHSA-qpr4)",
  "details" : "## Summary\n\nThe `fetch()` call for remote images in `packages/integrations/cloudflare/src/utils/image-binding-transform.ts` (line 28) uses the default `redirect: 'follow'` behavior. This allows the Cloudflare Worker to follow HTTP redirects to arbitrary URLs, bypassing the `isRemoteAllowed()` domain allowlist check which only validates the initial URL.\n\nAll three other image fetch paths in the codebase correctly use `{ redirect: 'manual' }`. This is an incomplete fix for GHSA-qpr4-c339-7vq8.\n\nConfirmed on HEAD.\n\n## Root Cause\n\n`image-binding-transform.ts` line 28:\n\n    const content = await (isRemotePath(href) ? fetch(imageSrc) : assets.fetch(imageSrc));\n\nMissing `{ redirect: 'manual' }`. The three protected paths:\n\n    // image-passthrough-endpoint.ts:23\n    response = await fetch(href, { redirect: 'manual' });\n\n    // assets/endpoint/shared.ts:11\n    const res = await fetch(src, { redirect: 'manual' });\n\n    // assets/utils/remoteProbe.ts:53\n    const response = await fetch(url, { redirect: 'manual' });\n\n## PoC\n\nDemonstrated with Node.js that `fetch()` without `redirect: 'manual'` follows 302 redirects to arbitrary destinations:\n\n    # Server A (allowed domain) returns 302 → Server B (internal)\n    fetch('http://allowed:19741/img.jpg')                        → follows 302 → hits http://internal:19742/secret\n    fetch('http://allowed:19741/img.jpg', {redirect:'manual'})   → returns 302, internal server NOT hit\n\nAttack path: attacker finds an open redirect on an allowed domain, crafts `/_image?href=https://allowed-cdn.com/redirect?url=http://internal-service/`, and the Worker follows the redirect to the unauthorized destination.\n\n## Impact\n\nBypasses the `image.domains` and `image.remotePatterns` allowlist for the default Cloudflare image service (`cloudflare-binding`). Enables blind SSRF to domains not in the allowlist. Same vulnerability class as GHSA-qpr4-c339-7vq8 (HIGH) which fixed the passthrough endpoint but missed this one.\n\n## Suggested Fix\n\n    const content = await (isRemotePath(href) ? fetch(imageSrc, { redirect: 'manual' }) : assets.fetch(imageSrc));",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@astrojs/cloudflare"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "13.1.10"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/withastro/astro/security/advisories/GHSA-88gm-j2wx-58h6"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-41321"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/withastro/astro/commit/a43eb4b40b4f81530e3c9b5e2959495900320433"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-qpr4-c339-7vq8"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/withastro/astro"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/withastro/astro/releases/tag/%40astrojs%2Fcloudflare%4013.1.10"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-918" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-23T21:52:03Z",
    "nvd_published_at" : "2026-04-24T18:16:28Z"
  }
}