CVE-2025-66202 — Astro has an Authentication Bypass via Double URL Encoding, a bypass for CVE-2025-64765
Astro is a web framework. Versions 5.15.7 and below have a double URL encoding bypass which allows any unauthenticated attacker to bypass path-based authentication checks in Ast…
Published: 2025-12-08 · CVSS: 6.5 · CVSS 3.1
Astro is a web framework. Versions 5.15.7 and below have a double URL encoding bypass which allows any unauthenticated attacker to bypass path-based authentication checks in Astro middleware, granting unauthorized access to protected routes. While the original CVE-2025-64765 was fixed in v5.15.8, the fix is insufficient as it only decodes once. By using double-encoded URLs, attackers can still bypass authentication and access any route protected by middleware pathname checks. This issue is fixed in version 5.15.8.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7