{"api_version":"1","generated_at":"2026-09-02T03:59:40+00:00","cve":"CVE-2026-84640","urls":{"html":"https://cve.report/CVE-2026-84640","api":"https://cve.report/api/cve/CVE-2026-84640.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-84640","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-84640"},"summary":{"title":"One byte overflow read in mail parser","description":"A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.","state":"PUBLISHED","assigner":"mozilla","published_at":"2026-09-01 22:17:19","updated_at":"2026-09-01 22:17:19"},"problem_types":[],"metrics":[],"references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2063964","name":"https://bugzilla.mozilla.org/show_bug.cgi?id=2063964","refsource":"security@mozilla.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-88/","name":"https://www.mozilla.org/security/advisories/mfsa2026-88/","refsource":"security@mozilla.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-87/","name":"https://www.mozilla.org/security/advisories/mfsa2026-87/","refsource":"security@mozilla.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-86/","name":"https://www.mozilla.org/security/advisories/mfsa2026-86/","refsource":"security@mozilla.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-84640","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-84640","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Mozilla","product":"Thunderbird","version":"unaffected 140.15 140.* rpm","platforms":[]},{"source":"CNA","vendor":"Mozilla","product":"Thunderbird","version":"unaffected 153.2 153.* rpm","platforms":[]},{"source":"CNA","vendor":"Mozilla","product":"Thunderbird","version":"unaffected 155 * rpm","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[{"source":"CNA","value":"Ramesh Adhikari, Dr. Faruk Kazi (CoE-CNDS Lab, VJTI, Mumbai, India)","lang":"en"}],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"product":"Thunderbird","vendor":"Mozilla","versions":[{"lessThanOrEqual":"140.*","status":"unaffected","version":"140.15","versionType":"rpm"},{"lessThanOrEqual":"153.*","status":"unaffected","version":"153.2","versionType":"rpm"},{"lessThanOrEqual":"*","status":"unaffected","version":"155","versionType":"rpm"}]}],"credits":[{"lang":"en","value":"Ramesh Adhikari, Dr. Faruk Kazi (CoE-CNDS Lab, VJTI, Mumbai, India)"}],"descriptions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2."}],"value":"A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2."}],"providerMetadata":{"dateUpdated":"2026-09-01T21:44:15.623Z","orgId":"f16b083a-5664-49f3-a51e-8d479e5ed7fe","shortName":"mozilla"},"references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2063964"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-86/"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-87/"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-88/"}],"title":"One byte overflow read in mail parser"}},"cveMetadata":{"assignerOrgId":"f16b083a-5664-49f3-a51e-8d479e5ed7fe","assignerShortName":"mozilla","cveId":"CVE-2026-84640","datePublished":"2026-09-01T21:33:06.832Z","dateReserved":"2026-09-01T21:33:06.555Z","dateUpdated":"2026-09-01T21:44:15.623Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-01 22:17:19","lastModifiedDate":"2026-09-01 22:17:19","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"84640","Ordinal":"1","Title":"One byte overflow read in mail parser","CVE":"CVE-2026-84640","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"84640","Ordinal":"1","NoteData":"A maliciously constructed mail header could lead to a one byte read past the end of a buffer. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.","Type":"Description","Title":"One byte overflow read in mail parser"}]}}}