CVE-2026-109780 Critical · 9.8 EPSS 0.4%
Mitigation bypass in the DOM: Core & HTML component
Mozilla · Firefox
Summary
A mitigation bypass in the DOM: Core & HTML component of Mozilla Firefox allows protections implemented in that component to be circumvented. An attacker who can reach the affected browser over the network, without authentication or user interaction, can exploit this flaw.
Official description · NVD
Mitigation bypass in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 158 and Thunderbird 158.
Priority scorePatchfirst’s 0 to 100 ranking. It adds points for CISA KEV listing, ransomware use, EPSS, threat reports, public exploit code and CVSS. Every CVE page shows the breakdown. Breakdown
15.2 / 100
- Exploited
- Not confirmed
- Reports
- 0
- Tactics
- 0/15
Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
Disclosed on 13 Oct 2026. No public exploit code or confirmed exploitation is recorded.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
No techniques linkedNo ATT&CK techniques are linked to this CVE yet. MITRE CTID has not mapped it, and no report passage in the corpus ties it to a technique.
What security researchers reported
Not named in any threat report yetAlso mentioned in 9 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Known_Cve | Oct 22, 2026 | Part 1/421 Oct 2026
- Known_Cve | Oct 21, 2026 | Part 2/420 Oct 2026
- Known_Cve | Oct 20, 2026 | Part 2/419 Oct 2026
- Known_Cve | Oct 19, 2026 | Part 2/418 Oct 2026
- Known_Cve | Oct 18, 2026 | Part 2/417 Oct 2026
- Known_Cve | Oct 17, 2026 | Part 2/416 Oct 2026
- 3 more on OTX