CVE-2026-84142

Description

Internally found bugs present in Thunderbird 154. 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 155 and Thunderbird 155.

References

• https://bugzilla.mozilla.org/buglist.cgi?bug_id=2029421%2C2040889%2C2045313%2C2045435%2C2053578%2C2058621%2C2058626
• https://bugzilla.mozilla.org/buglist.cgi?bug_id=2048796%2C2053150%2C2057356
• https://www.mozilla.org/security/advisories/mfsa2026-82/
• https://www.mozilla.org/security/advisories/mfsa2026-86/