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TI-2025-40706 Aliases CVE-2025-66202GHSA-whqg-ppgf-wp8c

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

Priority LOW 35CWE-647Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub.

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00314 24th percentileScored 2026-11-07
Fix Fixed astro (withastro): 5.15.8astro (npm): 5.15.8

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
withastroastrobefore 5.15.85.15.8Patch availableCNA
—astro (npm)before 5.15.85.15.8Patch availableGHSA-whqg-ppgf-wp8c
  • astro Vendorwithastro Affected before 5.15.8 Fixed in 5.15.8 Patch available CNA
  • astro (npm) Vendor— Affected before 5.15.8 Fixed in 5.15.8 Patch available GHSA-whqg-ppgf-wp8c

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:astro:astro:*:*:*:*:*:node.js:*:*before 5.15.8Vulnerablewithastro
  • cpe:2.3:a:astro:astro:*:*:*:*:*:node.js:*:* Versions before 5.15.8 Vulnerable ·withastro

Remediation

  • Fix · CNA astro (withastro) Fixed in 5.15.8
  • Fix · GHSA-whqg-ppgf-wp8c astro (npm) Fixed in 5.15.8 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-66202
  2. 2026-10-03 Alias added: GHSA-whqg-ppgf-wp8c

References

Patch 1

Advisory 3

Other 2

  • TI-2024-37142 Server source code is exposed to the public if sourcemaps are enabled CVSS 4.0HIGH 7.8
  • TI-2025-34958 Unauthorized third-party images in Astro’s _image endpoint CVSS 4.0MEDIUM 6.9
  • TI-2025-39915 Server-side request forgery in withastro astro CVSS 3.1MEDIUM 6.5
  • TI-2025-38274 Astro's `X-Forwarded-Host` is reflected with no validation CVSS 3.1MEDIUM 6.5
  • TI-2026-36915 Astro: Reflected XSS via unescaped slot name CVSS 3.1HIGH 7.1
  • TI-2025-40102 Astro is vulnerable to Reflected XSS via the server islands feature CVSS 3.1HIGH 7.1
See all 19 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences