Server-Side Request Forgery via /_image endpoint in Astro Cloudflare adapter

An attacker can exploit this SSRF vulnerability by crafting malicious image requests that target internal services or external resources. This could lead to information disclosure of sensitive data residing within the server's network, or potentially even allow the attacker to trigger actions on internal systems. The ability to serve content from arbitrary domains bypasses intended security controls and could be leveraged for phishing attacks or to inject malicious code into the website. The blast radius extends to any internal resources accessible from the server, and the impact can be significant depending on the sensitivity of those resources.

Astro websites utilizing the Cloudflare adapter with output: 'server' and imageService: 'compile' are at risk. This includes developers who have integrated external image sources into their Astro projects without proper validation and those using shared hosting environments where the server configuration might be less controllable.

• nodejs / server:

  npm list @astrojs/cloudflare

• nodejs / server:

  grep -r 'imageService: \'compile\'' ./astro.config.mjs ./astro.config.ts

• generic web: Check Astro site's /_image endpoint for unauthorized domain access by attempting to load an image from an external, non-approved domain.

1. 2025-09-04Disclosure

   disclosure

1. Reserviert2025-08-27
2. Veröffentlicht2025-09-04
3. Geändert2025-09-05
4. EPSS aktualisiert2026-03-23

The primary mitigation is to upgrade to @astrojs/cloudflare version 12.6.6 or later. If upgrading is not immediately feasible, consider implementing a strict allowlist of authorized image domains within your Astro configuration. Additionally, implement a Web Application Firewall (WAF) with rules to block requests to the /_image endpoint with suspicious or unauthorized URLs. Carefully review and restrict network access for the server running the Astro application to minimize the potential impact of a successful SSRF attack.