{"schemaVersion":3,"id":"CVE-2026-84641","aliases":["UBUNTU-CVE-2026-84641","DEBIAN-CVE-2026-84641"],"status":"published","duplicateOf":null,"title":null,"description":"A malicious IMAP server can trigger use-after-free and heap-memory disclosure by sending a crafted ID response. Heap contents can ultimately be persisted to prefs.js. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.","dates":{"published":"2026-09-01T21:33:07.410Z","modified":"2026-09-02T18:47:17.033Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":7.5,"severity":"high","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":7.5,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Ubuntu","score":7.5,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","exploitability":10,"impact":6,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Debian","score":7.5,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","exploitability":10,"impact":6,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"NVD","score":7.5,"severity":"high","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":0.00267,"percentile":0.1771,"severity":"low","asOf":"2026-10-19T00:00:00.000Z","change":{"pp":0,"baselineDate":"2026-09-19T00:00:00.000Z","baselineScore":0.00267},"history":[{"date":"2026-09-14T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-15T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-16T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-17T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-18T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-19T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00439,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00267,"percentile":0.1771}],"last30":[{"date":"2026-09-19T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-20T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-21T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-22T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-23T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-24T00:00:00.000Z","score":0.00439,"percentile":null},{"date":"2026-09-25T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-26T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-27T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-28T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-29T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-09-30T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-01T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-02T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-03T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-04T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-05T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-06T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-07T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-08T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-09T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-10T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-11T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-12T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-13T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-14T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-15T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-16T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-17T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-18T00:00:00.000Z","score":0.00267,"percentile":null},{"date":"2026-10-19T00:00:00.000Z","score":0.00267,"percentile":0.1771}]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-416","name":"Use After Free","description":"The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory \"belongs\" to the code that operates on the new pointer.","type":"weakness","status":"Stable","abstraction":"Variant","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/416.html"}],"affected":[{"vendor":"debian","product":"thunderbird","name":"thunderbird","label":"thunderbird","ecosystem":"Debian","cpePart":null,"purl":"pkg:deb/debian/thunderbird","purlType":"deb","versions":[{"text":"< 1:140.15.0esr-1~deb12u1","noFixRecorded":false,"fixedIn":null},{"text":"< 1:140.15.0esr-1~deb13u1","noFixRecorded":false,"fixedIn":null},{"text":"< 1:153.2.0esr-1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1:140.15.0esr-1~deb12u1 | < 1:140.15.0esr-1~deb13u1 | < 1:153.2.0esr-1","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"thunderbird","name":"thunderbird","label":"thunderbird","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/thunderbird","purlType":"deb","versions":[{"text":"All versions","noFixRecorded":true,"fixedIn":null}],"versionsText":"All versions (No fix recorded)","eol":null,"hubHref":null},{"vendor":"mozilla","product":"thunderbird","name":"Thunderbird","label":"thunderbird","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"< 140.15.0","noFixRecorded":false,"fixedIn":null},{"text":"≥ 141.0, < 153.2.0","noFixRecorded":false,"fixedIn":null},{"text":"≥ 154.0, < 155.0","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 140.15.0 | ≥ 141.0, < 153.2.0 | ≥ 154.0, < 155.0","eol":null,"hubHref":"/vendor/mozilla/thunderbird"}],"affectedCount":3,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2057805","label":"bugzilla.mozilla.org/show_bug.cgi?id=2057805","hostname":"bugzilla.mozilla.org","tags":["Permissions Required"]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-86/","label":"www.mozilla.org/security/advisories/mfsa2026-86/","hostname":"www.mozilla.org","tags":["Vendor Advisory"]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-87/","label":"www.mozilla.org/security/advisories/mfsa2026-87/","hostname":"www.mozilla.org","tags":["Vendor Advisory"]},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-88/","label":"www.mozilla.org/security/advisories/mfsa2026-88/","hostname":"www.mozilla.org","tags":["Vendor Advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-84641","label":"ubuntu.com/security/CVE-2026-84641","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-84641","label":"www.cve.org/CVERecord?id=CVE-2026-84641","hostname":"www.cve.org","tags":["REPORT"]},{"url":"https://www.mozilla.org/en-US/security/advisories/mfsa2026-87/#CVE-2026-84641","label":"www.mozilla.org/en-US/security/advisories/mfsa2026-87/","hostname":"www.mozilla.org","tags":["REPORT"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-84641","label":"security-tracker.debian.org/tracker/CVE-2026-84641","hostname":"security-tracker.debian.org","tags":["Advisory"]}],"lineage":{"upstream":[],"downstream":["MGASA-2026-0388","OPENSUSE-SU-2026:11678-1","RHSA-2026:70642","RHSA-2026:73130","RHSA-2026:73971","RHSA-2026:77627","RHSA-2026:77631","RHSA-2026:77632","RHSA-2026:80503","RHSA-2026:81912","RHSA-2026:81913","RHSA-2026:82122","SUSE-SU-2026:4268-1"],"duplicates":[],"related":["OPENSUSE-SU-2026:11678-1","SUSE-SU-2026:4268-1"]},"timeline":[{"kind":"published","date":"2026-09-01T21:33:07.410Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-09-02T18:47:17.033Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":30,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-20T11:39:12.678Z","stale":false,"partial":false}}