CVE-2026-0877

8.1 highEPSS 0.5%

Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 147, Firefox ESR 115.32, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.

Severity

CVSS 3.1

8.1 high

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

EPSS: 0.5% chance of exploitation in the next 30 days; higher than 40% of CVEs (scores of 2026-10-31)
CWE: CWE-693
Published: 2026-01-13
Modified: 2026-07-15
Record from: the NVD, synced 2026-10-19

Affected

mozilla:firefox
mozilla:thunderbird

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1999257
https://www.mozilla.org/security/advisories/mfsa2026-01/
https://www.mozilla.org/security/advisories/mfsa2026-02/
https://www.mozilla.org/security/advisories/mfsa2026-03/
https://www.mozilla.org/security/advisories/mfsa2026-04/

Check your stack JSON