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, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
https://www.mozilla.org/security/advisories/mfsa2026-61/
https://www.mozilla.org/security/advisories/mfsa2026-60/
https://www.mozilla.org/security/advisories/mfsa2026-59/
https://www.mozilla.org/security/advisories/mfsa2026-58/
https://www.mozilla.org/security/advisories/mfsa2026-57/
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12328.json
https://bugzilla.redhat.com/show_bug.cgi?id=2489218
https://access.redhat.com/security/cve/CVE-2026-12328
https://access.redhat.com/errata/RHSA-2026:39706
https://access.redhat.com/errata/RHSA-2026:39428
https://access.redhat.com/errata/RHSA-2026:39142
https://access.redhat.com/errata/RHSA-2026:39141
https://access.redhat.com/errata/RHSA-2026:39011
https://access.redhat.com/errata/RHSA-2026:38753
https://access.redhat.com/errata/RHSA-2026:38751
https://access.redhat.com/errata/RHSA-2026:38750
https://access.redhat.com/errata/RHSA-2026:38506
https://access.redhat.com/errata/RHSA-2026:37391
https://access.redhat.com/errata/RHSA-2026:37210
https://access.redhat.com/errata/RHSA-2026:36103
https://access.redhat.com/errata/RHSA-2026:36102
https://access.redhat.com/errata/RHSA-2026:36101
https://access.redhat.com/errata/RHSA-2026:36100
https://access.redhat.com/errata/RHSA-2026:33445
https://access.redhat.com/errata/RHSA-2026:30846
https://access.redhat.com/errata/RHSA-2026:29940
https://access.redhat.com/errata/RHSA-2026:27734