CVE-2026-109780: Mitigation Bypass
Source GCVE Database
Not known to be exploited · CVSS 9.8 Critical.
Data as of 26 Oct 2026, 22:42 UTC
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 13 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
Users should update to Firefox version 158 or later, where this vulnerability has been fixed. No additional mitigation actions are required beyond applying the official update.
Description
CVE-2026-109780 is a critical mitigation bypass vulnerability in the DOM: Core & HTML component of Firefox. This flaw allows attackers to bypass security mitigations, potentially leading to full compromise of confidentiality, integrity, and availability. The issue was fixed in Firefox version 158.