CVE-2026-5734

CRITICAL9.8

Memory safety bugs fixed in Firefox ESR 140.9.1, Thunderbird ESR 140.9.1, Firefox 149.0.2 and Thunderbird 149.0.2

Published Apr 7, 2026

Modified 2 days ago

Details

Memory safety bugs present in Firefox ESR 140.9.0, Thunderbird ESR 140.9.0, Firefox 149.0.1 and Thunderbird 149.0.1. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 149.0.2, Firefox ESR 140.9.1, Thunderbird 149.0.2, and Thunderbird 140.9.1.

References

WEB

https://bugzilla.mozilla.org/buglist.cgi?bug_id=2022369%2C2023026%2C2023545%2C2023555%2C2023958%2C2025422%2C2025468%2C2025492%2C2025505

ADVISORY

https://www.cve.org/CVERecord?id=CVE-2026-5734

WEB

https://www.mozilla.org/security/advisories/mfsa2026-25/

WEB

https://www.mozilla.org/security/advisories/mfsa2026-27/

WEB

https://www.mozilla.org/security/advisories/mfsa2026-28/

WEB