A maliciously constructed IMAP line could cause an out-of-bounds buffer read. This vulnerability was fixed in Thunderbird 156 and Thunderbird 140.16.
https://www.mozilla.org/security/advisories/mfsa2026-95/
https://www.mozilla.org/security/advisories/mfsa2026-94/
https://bugzilla.mozilla.org/show_bug.cgi?id=2060488
Source: Mitre, NVD
Published: 2026-09-15
Updated: 2026-09-15
Base Score: 6.4
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:P
Severity: Medium
Base Score: 9.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Severity: Critical