{"id":"CVE-2025-0239","state":"PUBLISHED","title":"Alt-Svc ALPN validation failure when redirected","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.","publishedAt":"2025-01-07T16:07:06.317Z","updatedAt":"2026-04-13T14:30:01.233Z","severity":{"score":4,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","source":"CISA-ADP"},"assigner":"mozilla","products":["Mozilla Firefox","Mozilla Thunderbird"],"affected":[{"vendor":"Mozilla","product":"Firefox","versions":[{"version":"128.6","status":"unaffected","lessThanOrEqual":"128.*","versionType":"rpm"},{"version":"134","status":"unaffected","lessThanOrEqual":"*","versionType":"rpm"}]},{"vendor":"Mozilla","product":"Thunderbird","versions":[{"version":"128.6","status":"unaffected","lessThanOrEqual":"128.*","versionType":"rpm"},{"version":"134","status":"unaffected","lessThanOrEqual":"*","versionType":"rpm"}]}],"references":["https://bugzilla.mozilla.org/show_bug.cgi?id=1929156","https://www.mozilla.org/security/advisories/mfsa2025-01/","https://www.mozilla.org/security/advisories/mfsa2025-02/","https://www.mozilla.org/security/advisories/mfsa2025-04/","https://www.mozilla.org/security/advisories/mfsa2025-05/","https://lists.debian.org/debian-lts-announce/2025/01/msg00004.html"],"weaknesses":["CWE-295"],"ingestedAt":"2026-10-29T20:08:20.985Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/0xxx/CVE-2025-0239.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-0239","state":"PUBLISHED","datePublished":"2025-01-07T16:07:06.317Z","dateUpdated":"2026-04-13T14:30:01.233Z","assignerShortName":"mozilla","assignerOrgId":"f16b083a-5664-49f3-a51e-8d479e5ed7fe","dateReserved":"2025-01-06T14:49:04.597Z"},"containers":{"cna":{"title":"Alt-Svc ALPN validation failure when redirected","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Mozilla","product":"Firefox","versions":[{"version":"128.6","status":"unaffected","lessThanOrEqual":"128.*","versionType":"rpm"},{"version":"134","status":"unaffected","lessThanOrEqual":"*","versionType":"rpm"}]},{"vendor":"Mozilla","product":"Thunderbird","versions":[{"version":"128.6","status":"unaffected","lessThanOrEqual":"128.*","versionType":"rpm"},{"version":"134","status":"unaffected","lessThanOrEqual":"*","versionType":"rpm"}]}],"references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=1929156"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-01/"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-02/"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-04/"},{"url":"https://www.mozilla.org/security/advisories/mfsa2025-05/"}],"providerMetadata":{"shortName":"mozilla","orgId":"f16b083a-5664-49f3-a51e-8d479e5ed7fe","dateUpdated":"2026-04-13T14:30:01.233Z"},"credits":[{"lang":"en","value":"Paul Gerste"}]},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":4,"attackVector":"LOCAL","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","integrityImpact":"LOW","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"NONE","privilegesRequired":"NONE","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"timestamp":"2025-01-08T16:33:42.534195Z","id":"CVE-2025-0239","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-295","type":"CWE","lang":"en","description":"CWE-295 Improper Certificate Validation"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2025-01-08T16:36:07.964Z"}},{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00004.html"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2025-11-03T22:33:39.114Z"}}]}}}