CVE-2025-66202 json
Astro has an Authentication Bypass via Double URL Encoding, a bypass for CVE-2025-64765
published 2025-12-08 11 mo ago modified 2026-10-07 32 d ago also EUVD-2025-201717 , GHSA-whqg-ppgf-wp8c
- cvss
- 6.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 26%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 11 mo ago
Exploit prediction
0.33% chance of exploitation in the next 30 days, higher than 26% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
| GitHub | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
| NVD | 3.1 | 6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | astro | <5.15.8 |
5.15.8 |
Affected products
- withastro astro
Classification
- Weakness
-
- CWE-647 Use of Non-Canonical URL Paths for Authorization Decisions
References
-
github.com
/withastro/astro/commit/6f800813516b07bbe12c666a92937525fddb58ce
web, patch
-
github.com
/withastro/astro/security/advisories/GHSA-whqg-ppgf-wp8c
web, vendor-advisory
-
github.com
/withastro/astro/security/advisories/GHSA-ggxq-hp9w-j794
web, not-applicable
-
nvd.nist.gov
/vuln/detail/CVE-2025-64765
advisory
-
nvd.nist.gov
/vuln/detail/CVE-2025-66202
advisory
-
github.com
/withastro/astro
package
Sources
- CVE List CVE-2025-66202
- GitHub Advisory GHSA-whqg-ppgf-wp8c
- NVD CVE-2025-66202
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.