- Critical 9.6
CVE-2026-109750
Site isolation issue in the DOM: Web Authentication component. This vulnerability was fixed in Firefox 158 and Thunderbird 158.
Scores
The facts
- Published
- 13 October 2026
- Last changed
- 19 October 2026
- NVD status
- Deferred
- Severity
- Critical, CVSS 9.6 out of 10 (version 3.1)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H - Weakness
- Known exploited
- Not in the CISA Known Exploited Vulnerabilities catalogue in this build.
- EPSS
- 0.2% chance of exploitation activity in the next 30 days (percentile 12).
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