Paper/Archive/CVE-2026-109780

CVE-2026-109780

Mozilla Firefox — Mitigation bypass in the DOM: Core & HTML component

EPSS 0.4%CVSS 9.8

critical.is priorityof 100

35

CVSS 9.8 (ADP)9.8 / 10 × 3029.4 Not in CISA KEV+300.0 EPSS percentile 30.1.301 × 206.0 No public exploit+100.0 SSVC exploitation: none+100.0

Description · from the CVE record

Mitigation bypass in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 158 and Thunderbird 158.

Affected

ProductAffectedFixed inSource

Firefoxsee advisory158CNA

Thunderbirdsee advisory158CNA

Scores by source

CISA ADP9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refbugzilla.mozilla.org/show_bug.cgi?id=2072775 refmozilla.org/security/advisories/mfsa2026-106 refmozilla.org/security/advisories/mfsa2026-109