{"cve":"CVE-2025-66202","nvd":{"published":"2025-12-09T00:15:48.977","modified":"2026-10-07T20:10:01.970","status":"Analyzed","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","score":6.5},"cwes":["CWE-647"],"references":["https://github.com/withastro/astro/commit/6f800813516b07bbe12c666a92937525fddb58ce","https://github.com/withastro/astro/security/advisories/GHSA-ggxq-hp9w-j794","https://github.com/withastro/astro/security/advisories/GHSA-whqg-ppgf-wp8c"],"products":["astro:astro"],"source":"nvd","synced_at":"2026-10-19T22:16:40.427100871+00:00"},"epss":{"cve":"CVE-2025-66202","score":0.00314,"percentile":0.24045,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-whqg-ppgf-wp8c","url":"https://osv.dev/vulnerability/GHSA-whqg-ppgf-wp8c","summary":"Astro has an Authentication Bypass via Double URL Encoding, a bypass for CVE-2025-64765","modified":"2026-02-04T02:27:12.689316Z","packages":[{"ecosystem":"npm","name":"astro","purl":"pkg:npm/astro","ranges":["<5.15.8"],"fixed":["5.15.8"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}