CVE-2026-74989

Published: Aug 18, 2026Modified: Sep 1, 2026

9.8

Vector

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

Exploitability: 3.9 / Impact: 5.9

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

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.

Affected (2)

Products: Mozilla: Firefox, Thunderbird

2 products

Configuration A

2 vulnerable

Vulnerable Software	Affected Versions
Mozilla Firefox	Before 154.0.0
Mozilla Thunderbird	Before 154.0

Related CWEs

Improper Restriction of Operations within the Bounds of a Memory Buffer

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

References (4)

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

Source: security@mozilla.org

Not Applicable

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

Source: security@mozilla.org

Not Applicable

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

Source: security@mozilla.org

Vendor Advisory

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

Source: security@mozilla.org

Vendor Advisory

Timeline

No history available yet.