CVE-2026-2771

Undefined behavior in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

Score: CVSS 3.1 9.8 Critical
Status: Modified - security@mozilla.org
Published: 2026-02-24
Last modified: 2026-09-21
Weaknesses: CWE-125

Affected products

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2014593
https://www.mozilla.org/security/advisories/mfsa2026-13/
https://www.mozilla.org/security/advisories/mfsa2026-14/
https://www.mozilla.org/security/advisories/mfsa2026-15/
https://www.mozilla.org/security/advisories/mfsa2026-16/
https://www.mozilla.org/security/advisories/mfsa2026-17/
https://access.redhat.com/errata/RHSA-2026:3338
https://access.redhat.com/errata/RHSA-2026:3339
https://access.redhat.com/errata/RHSA-2026:3361
https://access.redhat.com/errata/RHSA-2026:3491
https://access.redhat.com/errata/RHSA-2026:3492
https://access.redhat.com/errata/RHSA-2026:3493
https://access.redhat.com/errata/RHSA-2026:3494
https://access.redhat.com/errata/RHSA-2026:3495
https://access.redhat.com/errata/RHSA-2026:3496
https://access.redhat.com/errata/RHSA-2026:3497
https://access.redhat.com/errata/RHSA-2026:3515
https://access.redhat.com/errata/RHSA-2026:3516
https://access.redhat.com/errata/RHSA-2026:3517
https://access.redhat.com/errata/RHSA-2026:3976
https://access.redhat.com/errata/RHSA-2026:3978
https://access.redhat.com/errata/RHSA-2026:3979
https://access.redhat.com/errata/RHSA-2026:3980
https://access.redhat.com/errata/RHSA-2026:3981
https://access.redhat.com/errata/RHSA-2026:3982
https://access.redhat.com/errata/RHSA-2026:3983
https://access.redhat.com/errata/RHSA-2026:3984
https://access.redhat.com/errata/RHSA-2026:4022
https://access.redhat.com/errata/RHSA-2026:4152
https://access.redhat.com/errata/RHSA-2026:4260