{"id":"CVE-2026-126133","state":"PUBLISHED","title":"Calendar server credentials could be sent to an HTTP proxy","description":"When a CalDAV or ICS calendar was accessed through an HTTP proxy that requested authentication, Thunderbird could answer the proxy with the calendar server's username and password. This affected both setting up a new calendar and syncing existing calendars, where a saved password could be sent without any user interaction. A malicious or compromised proxy could use this to obtain the calendar credentials, even for calendars served over HTTPS. This vulnerability was fixed in Thunderbird 160 and Thunderbird 153.7.","publishedAt":"2026-11-10T18:59:54.427Z","updatedAt":"2026-11-10T20:24:06.988Z","severity":null,"assigner":"mozilla","products":["Mozilla Thunderbird"],"affected":[{"vendor":"Mozilla","product":"Thunderbird","versions":[{"version":"153.7","status":"unaffected","lessThanOrEqual":"153.*","versionType":"rpm"},{"version":"160","status":"unaffected","lessThanOrEqual":"*","versionType":"rpm"}]}],"references":["https://bugzilla.mozilla.org/show_bug.cgi?id=2083485","https://www.mozilla.org/security/advisories/mfsa2026-128/","https://www.mozilla.org/security/advisories/mfsa2026-129/"],"weaknesses":[],"ingestedAt":"2026-11-10T20:32:04.536Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/126xxx/CVE-2026-126133.json","commit":"56b6c26af892d89b485e301e3e32feb453abafc8","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-126133","state":"PUBLISHED","datePublished":"2026-11-10T18:59:54.427Z","dateUpdated":"2026-11-10T20:24:06.988Z","assignerShortName":"mozilla","assignerOrgId":"f16b083a-5664-49f3-a51e-8d479e5ed7fe","dateReserved":"2026-11-10T18:59:53.798Z"},"containers":{"cna":{"title":"Calendar server credentials could be sent to an HTTP proxy","descriptions":[{"lang":"en","value":"When a CalDAV or ICS calendar was accessed through an HTTP proxy that requested authentication, Thunderbird could answer the proxy with the calendar server's username and password. This affected both setting up a new calendar and syncing existing calendars, where a saved password could be sent without any user interaction. A malicious or compromised proxy could use this to obtain the calendar credentials, even for calendars served over HTTPS. This vulnerability was fixed in Thunderbird 160 and Thunderbird 153.7."}],"affected":[{"vendor":"Mozilla","product":"Thunderbird","versions":[{"version":"153.7","status":"unaffected","lessThanOrEqual":"153.*","versionType":"rpm"},{"version":"160","status":"unaffected","lessThanOrEqual":"*","versionType":"rpm"}]}],"references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2083485"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-128/"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-129/"}],"providerMetadata":{"shortName":"mozilla","orgId":"f16b083a-5664-49f3-a51e-8d479e5ed7fe","dateUpdated":"2026-11-10T20:24:06.988Z"},"credits":[{"lang":"en","value":"Christopher Bohn (Protectstar Inc.)"}]}}}}