CVE-2026-74989

critical

Description

Internally found bugs present in Thunderbird 153. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited. This vulnerability was fixed in Firefox 154 and Thunderbird 154.

References

https://www.mozilla.org/security/advisories/mfsa2026-78/

https://www.mozilla.org/security/advisories/mfsa2026-74/

https://bugzilla.mozilla.org/buglist.cgi?bug_id=2027388%2C2029750%2C2029794%2C2043298%2C2045126%2C2049810%2C2051741

https://bugzilla.mozilla.org/buglist.cgi?bug_id=2022257%2C2027351%2C2027380%2C2029289

Details

Source: Mitre, NVD

Published: 2026-08-18

Updated: 2026-08-18

Risk Information

CVSS v2

Base Score: 7.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

Severity: High

CVSS v3

Base Score: 9.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: Critical