{"id":"CVE-2026-103500","title":"An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or equal to 2GB in size","summary":"An attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or equal to 2GB in size. This vulnerability was fixed in Thunderbird 157, Thunderbird 140.17, and Thunderbird 153.4.","severity":"medium","cvss":6.1,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H","cwe":["CWE-787","CWE-122"],"vendor":"mozilla","product":"thunderbird","affected":["thunderbird < 140.17.0","thunderbird >= 141.0, < 153.4.0","thunderbird >= 154.0, < 157.0"],"patched":["thunderbird 157.0"],"published":"2026-09-30","updated":"2026-10-16","sourceUpdated":"2026-10-16T19:17:01.550","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-103500","references":[{"url":"https://bugzilla.mozilla.org/show_bug.cgi?id=2070267","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-101/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-102/","label":"security@mozilla.org"},{"url":"https://www.mozilla.org/security/advisories/mfsa2026-103/","label":"security@mozilla.org"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-103500.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-103500"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2544154"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-103500"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-103500"}],"tags":["nvd","cve.org","csaf","vex","red-hat","score-dispute"],"epss":0.00277,"epssPercentile":0.20021,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-10-16T18:33:49.871087Z"},"scores":{"nvd":6.1,"vendor":8.8,"adp":6.3},"ingestedAt":"2026-09-30T18:17:24.565Z","slug":"CVE-2026-103500","body":"## Overview\n\nAn attacker could cause a heap buffer overflow by getting a user to open an email that is greater than or equal to 2GB in size. This vulnerability was fixed in Thunderbird 157, Thunderbird 140.17, and Thunderbird 153.4.\n\n## Affected\n\n- `thunderbird < 140.17.0`\n- `thunderbird >= 141.0, < 153.4.0`\n- `thunderbird >= 154.0, < 157.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `thunderbird 157.0`\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · updated 2026-10-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-103500.json)","depth":"sunlit","depthScore":34,"depthScoreParts":{"impact":33.6,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":222392,"id":"CVE-2026-103500","ts":1792076986275,"field":"cvss","old":"8.8","new":"6.1"},{"seq":222391,"id":"CVE-2026-103500","ts":1792076986275,"field":"severity","old":"high","new":"medium"},{"seq":214171,"id":"CVE-2026-103500","ts":1790841320557,"field":"cvss","old":null,"new":"8.8"},{"seq":214170,"id":"CVE-2026-103500","ts":1790841320557,"field":"severity","old":"none","new":"high"}]}