{"id":"CVE-2025-66202","title":"Astro is a web framework","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 rou…","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","cwe":["CWE-647"],"vendor":"astro","product":"astro","affected":["astro < 5.15.8"],"patched":["astro 5.15.8"],"published":"2025-12-09","updated":"2026-10-07","sourceUpdated":"2026-10-07T20:10:01.970","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-66202","references":[{"url":"https://github.com/withastro/astro/commit/6f800813516b07bbe12c666a92937525fddb58ce","label":"security-advisories@github.com"},{"url":"https://github.com/withastro/astro/security/advisories/GHSA-ggxq-hp9w-j794","label":"security-advisories@github.com"},{"url":"https://github.com/withastro/astro/security/advisories/GHSA-whqg-ppgf-wp8c","label":"security-advisories@github.com"}],"tags":["nvd"],"epss":0.00314,"epssPercentile":0.22183,"ingestedAt":"2026-10-07T20:46:46.779Z","slug":"CVE-2025-66202","body":"## Overview\n\nAstro 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.\n\n## Affected\n\n- `astro < 5.15.8`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `astro 5.15.8`","depth":"sunlit","depthScore":36,"depthScoreParts":{"impact":35.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}