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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-66202
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-12-09 00:15:48 UTC
Updated2026-10-07 20:10:01 UTC
DescriptionAstro 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.

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

EPSS: 0.003140000 probability, percentile 0.222600000 (date 2026-10-07)

Problem Types: CWE-647 | CWE-647 CWE-647: Use of Non-Canonical URL Paths for Authorization Decisions

VersionSourceTypeScoreSeverityVector
3.1[email protected]Primary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
3.1[email protected]Secondary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
3.1CNADECLARED6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Astro Astro All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Withastro Astro affected < 5.15.8 Not specified

References

ReferenceSourceLinkTags
github.com/withastro/astro/security/advisories/GHSA-ggxq-hp9w-j794 [email protected] github.com Not Applicable
github.com/withastro/astro/security/advisories/GHSA-whqg-ppgf-wp8c [email protected] github.com Vendor Advisory
github.com/withastro/astro/commit/6f800813516b07bbe12c666a92937525fddb58ce [email protected] github.com Patch
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