CVE-2026-12328 PUBLISHED

Memory safety bugs present in Firefox ESR 115.36, Firefox ESR 140.11, Thunderbird ESR 140.11, Firefox 151 and Thunderbird 151. 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 152, Firefox ESR 140.12, and Firefox ESR 115.37.

• Andrew McCreight, Randell Jesup, Tom Ritter and the Mozilla Fuzzing Team

• High Severity memory safety bugs fixed in Firefox ESR 115.37, Firefox ESR 140.12, Thunderbird ESR 140.12, Firefox 152 and Thunderbird 152
• https://www.mozilla.org/security/advisories/mfsa2026-57/
• https://www.mozilla.org/security/advisories/mfsa2026-58/
• https://www.mozilla.org/security/advisories/mfsa2026-59/