Executive brief
Astro's Cloudflare integration provides image optimization for websites built with Astro. A vulnerability in the image-binding-transform endpoint allows attackers to bypass domain allowlist restrictions by following HTTP redirects to internal or unauthorized servers, potentially exposing sensitive internal services. Exploitation requires high privileges and complex conditions, but enables blind access to internal resources not normally allowed.
Technical details
This is a Server-Side Request Forgery (SSRF) vulnerability in the image-binding-transform endpoint of @astrojs/cloudflare. The root cause is that the fetch() call at packages/integrations/cloudflare/src/utils/image-binding-transform.ts line 28 uses the default redirect: 'follow' behavior instead of the secure redirect: 'manual' setting used elsewhere in the codebase. An attacker can craft a malicious URL that points to an allowed domain configured in image.domains or image.remotePatterns, but which contains an open redirect to an internal or unauthorized service. When the Cloudflare Worker processes the image request, it follows the redirect and fetches content from the internal destination, bypassing the allowlist. This is an incomplete fix for CVE-2025-XXXXX (GHSA-qpr4), which patched three other image fetch paths but missed this one. Exploitation requires high privileges and the ability to find an open redirect on an allowed domain. The CVSS score reflects limited impact (availability only) with high complexity requirements.
Affected products
- Astro @astrojs/cloudflare <13.1.10
Timeline
- 2026-04-23: disclosed: CVE-2026-41321 and GHSA-88gm-j2wx-58h6 published
- 2026-04-23: patched: Fixed in @astrojs/cloudflare 13.1.10