CVE-2026-25545
Severity CVSS v4.0:
MEDIUM
Type:
CWE-918
Server-Side Request Forgery (SSRF)
Publication date:
24/02/2026
Last modified:
24/02/2026
Description
Astro is a web framework. Prior to version 9.5.4, 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. 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). Version 9.5.4 fixes the issue.
Impact
Base Score 4.0
6.90
Severity 4.0
MEDIUM