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Medium 6.5Published Dec 8, 2025

CVE-2025-66202Astro has an Authentication Bypass via Double URL Encoding, a bypass for CVE-2025-64765

Updated under an hour ago ()

Does this affect you?

It affects withastro astro and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Weakness (CWE)
CWE-647
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Analyzed
Record last updated
Dec 9, 2025
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
withastro astro
withastro:astro (from the name)
before 5.15.8
CNA record
astro astro
astro:astro
before 5.15.8
NVD

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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