{"id":"UBUNTU-CVE-2026-84640","details":"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.","modified":"2026-09-16T14:03:37.567591855Z","published":"2026-09-01T22:17:00Z","upstream":["CVE-2026-84640"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-84640"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-84640"},{"type":"REPORT","url":"https://www.mozilla.org/en-US/security/advisories/mfsa2026-87/#CVE-2026-84640"}],"affected":[{"package":{"name":"thunderbird","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/thunderbird?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:91.1.2+build1-0ubuntu1","1:91.3.0+build2-0ubuntu1","1:91.3.1+build1-0ubuntu1","1:91.3.2+build1-0ubuntu1","1:91.4.0+build1.1-0ubuntu1","1:91.4.0+build2-0ubuntu1","1:91.5.0+build1-0ubuntu1","1:91.5.1+build1-0ubuntu1","1:91.6.1+build1-0ubuntu1","1:91.7.0+build1-0ubuntu1","1:91.7.0+build2-0ubuntu1","1:91.8.0+build2-0ubuntu1","1:91.9.1+build1-0ubuntu0.22.04.1","1:91.11.0+build2-0ubuntu0.22.04.1","1:102.2.2+build1-0ubuntu0.22.04.1","1:102.4.2+build2-0ubuntu0.22.04.1","1:102.7.1+build2-0ubuntu0.22.04.1","1:102.8.0+build2-0ubuntu0.22.04.1","1:102.9.0+build1-0ubuntu0.22.04.1","1:102.10.0+build2-0ubuntu0.22.04.1","1:102.11.0+build1-0ubuntu0.22.04.1","1:102.13.0+build1-0ubuntu0.22.04.1","1:102.15.0+build1-0ubuntu0.22.04.1","1:102.15.1+build1-0ubuntu0.22.04.1","1:115.3.1+build1-0ubuntu0.22.04.2","1:115.4.1+build1-0ubuntu0.22.04.1","1:115.5.0+build1-0ubuntu0.22.04.1","1:115.6.0+build2-0ubuntu0.22.04.1","1:115.8.1+build1-0ubuntu0.22.04.1","1:115.9.0+build1-0ubuntu0.22.04.1","1:115.10.1+build1-0ubuntu0.22.04.1","1:115.11.0+build2-0ubuntu0.22.04.1","1:115.12.0+build3-0ubuntu0.22.04.1","1:115.13.0+build5-0ubuntu0.22.04.1","1:115.15.0+build1-0ubuntu0.22.04.1","1:115.16.0+build2-0ubuntu0.22.04.1","1:115.18.0+build1-0ubuntu0.22.04.1","1:128.12.0+build1-0ubuntu0.22.04.1","1:140.7.1+build1-0ubuntu0.22.04.1"],"ecosystem_specific":{"binaries":[{"binary_name":"thunderbird","binary_version":"1:140.7.1+build1-0ubuntu0.22.04.1"},{"binary_version":"1:140.7.1+build1-0ubuntu0.22.04.1","binary_name":"thunderbird-gnome-support"},{"binary_version":"1:140.7.1+build1-0ubuntu0.22.04.1","binary_name":"thunderbird-mozsymbols"},{"binary_name":"xul-ext-calendar-timezones","binary_version":"1:140.7.1+build1-0ubuntu0.22.04.1"},{"binary_name":"xul-ext-gdata-provider","binary_version":"1:140.7.1+build1-0ubuntu0.22.04.1"},{"binary_name":"xul-ext-lightning","binary_version":"1:140.7.1+build1-0ubuntu0.22.04.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-84640.json"}},{"package":{"name":"thunderbird","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/thunderbird?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1:115.3.1+build1-0ubuntu1","1:115.4.1+build1-0ubuntu1","1:115.4.3+build1-0ubuntu1","1:115.5.0+build1-0ubuntu1","1:115.5.1+build1-0ubuntu1","1:115.5.2+build2-0ubuntu1","1:115.6.0+build1-0ubuntu1","1:115.6.0+build2-0ubuntu1","1:115.6.1+build1-0ubuntu1","1:115.8.0+build1-0ubuntu1","1:115.8.1+build1+snap2","1:115.8.1+build1+snap3","2:1snap1-0ubuntu1","2:1snap1-0ubuntu3"],"ecosystem_specific":{"binaries":[{"binary_version":"2:1snap1-0ubuntu3","binary_name":"thunderbird"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-84640.json"}},{"package":{"name":"thunderbird","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/thunderbird?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2:1snap1-0ubuntu3","2:1snap1-0ubuntu4","2:1snap1-0ubuntu5"],"ecosystem_specific":{"binaries":[{"binary_version":"2:1snap1-0ubuntu5","binary_name":"thunderbird"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-84640.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"},{"type":"Ubuntu","score":"medium"}]}