{"id":"CVE-2025-0239","url":"https://www.cyber-defence.io/tools/cve/CVE-2025-0239","generatedAt":"2026-10-28T02:18:11.991Z","title":"When using Alt-Svc, ALPN did not properly validate certificates when the original server is redirecting to an insecure site.","description":"When using Alt-Svc, ALPN did not properly validate certificates when the original server is redirecting to an insecure site. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.","published":"2025-01-07T16:15:39.000Z","lastModified":"2026-10-05T15:10:01.000Z","status":"Modified","sourceIdentifier":"security@mozilla.org","cvss":{"version":"3.1","score":4,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"},"cwe":["CWE-295"],"affected":["mozilla/firefox","mozilla/thunderbird"],"epss":{"score":0.00227,"percentile":0.13299,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1929156","tags":["Issue Tracking","Permissions Required"],"source":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-01/","tags":["Vendor Advisory"],"source":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-02/","tags":["Vendor Advisory"],"source":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-04/","tags":["Vendor Advisory"],"source":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-05/","tags":["Vendor Advisory"],"source":"security@mozilla.org"},{"url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00004.html","source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-0239","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}