CVE-2025-66202

Astro has an Authentication Bypass via Double URL Encoding, a bypass for CVE-2025-64765

Published: Dec 8, 2025Updated: Dec 10, 2025 Sources: CVE List NVD GHSACWE-647

6.5MEDIUM

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:LAttack Complexity

Low

PR:NPrivileges Required

None

UI:NUser Interaction

None

Scope

S:UScope

Unchanged

Impact

C:LConfidentiality

Low

I:LIntegrity

Low

A:NAvailability

None

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Weaknesses

CWE-647

Affected Products

withastro

oss-projectaka @astrojs/cloudflare, astro

astroLibrary

OSS Libraries / web-framework

package-ecosystem

oss-project·USaka @astrojs/node, @astrojs/cloudflare

astroMixed

OSS Libraries / web-framework

Exploitability

Official Patch Available

References

https://github.com/withastro/astro/security/advisories/GHSA-whqg-ppgf-wp8c

github.com

https://github.com/withastro/astro/security/advisories/GHSA-ggxq-hp9w-j794

github.com

https://github.com/withastro/astro/commit/6f800813516b07bbe12c666a92937525fddb58ce

github.com

and 3 more references View all →

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