CVE-2026-8969
HighCVSS 8.1Exploitation Probability (EPSS)
Low risk21th percentile - higher than 21% of all known CVEs
Summary
In Firefox and Thunderbird 151, a mitigation bypass vulnerability in the DOM: Security component was fixed. An attacker could bypass security measures.
Risk Assessment
Bypassing security measures could allow an attacker to perform unauthorized actions in the browser or email client.
Recommendation
Update Firefox and Thunderbird to version 151 or later.
Other vulnerabilities in Firefox
See all- CVE-2026-84141Critical
Integer overflow in the Graphics: ImageLib component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.
- CVE-2026-84140Critical
Site isolation issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.
- CVE-2026-84134Critical
Other issue in the Profile Backup component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.
- CVE-2026-84133Critical
Site isolation issue in the DOM: Push Subscriptions component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.
- CVE-2026-84129Critical
The vulnerability concerns a site isolation issue in the DOM: Navigation component in Firefox and Thunderbird. The flaw was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.
- CVE-2026-84121Critical
Sandbox escape due to use-after-free in the DOM: Security component. This vulnerability was fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
- CVE-2026-84119Critical
Sandbox escape vulnerability due to use-after-free in the DOM: Navigation component. Fixed in Firefox 155, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.
- CVE-2026-75874Critical
Sandbox escape in the Remote Settings Client component. Fixed in Firefox 154, Thunderbird 154, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 140.15, and Thunderbird 153.2.
- CVE-2026-74986Critical
Site isolation issue in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
- CVE-2026-74985Critical
Privilege escalation in the Enterprise Policies component. This vulnerability was fixed in Firefox 154, Firefox ESR 153.1, Thunderbird 154, and Thunderbird 153.1.
Original NVD description (English source)
Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.