CVE-2026-8401
CriticalCVSS 9.8Exploitation Probability (EPSS)
Low risk23th percentile - higher than 23% of all known CVEs
Summary
A sandbox escape vulnerability exists in the Profile Backup component of Firefox and Thunderbird. This flaw was fixed in Firefox 150.0.3, Firefox ESR 115.36, Firefox ESR 140.11, and Thunderbird 140.11.
Risk Assessment
An attacker could exploit this vulnerability to bypass process isolation and gain access to sensitive data or execute code outside the sandbox, posing a serious risk to system confidentiality and integrity.
Recommendation
Immediately update Firefox to version 150.0.3 or later, Firefox ESR to 115.36/140.11, and Thunderbird to version 140.11.
Other vulnerabilities in Firefox
See all- CVE-2026-106016Unknown
A vulnerability in the file handling component of the Firefox browser allows bypassing security mitigations. The issue was fixed in version 157.0.1.
- CVE-2026-100829Critical
Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.
- CVE-2026-100828Critical
Mitigation bypass in the Bookmarks & History component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.
- CVE-2026-100819Critical
Sandbox escape due to incorrect boundary conditions in the XPCOM component. Fixed in multiple Firefox and Thunderbird versions.
- CVE-2026-100818Critical
Sandbox escape due to use-after-free in the Widget: Gtk component. Fixed in multiple Firefox and Thunderbird versions.
- CVE-2026-100811Critical
Sandbox escape due to use-after-free in the DOM: Core & HTML component. Fixed in multiple Firefox and Thunderbird versions.
- CVE-2026-100810Critical
Other issue in the DevTools component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
- CVE-2026-100804Critical
Sandbox escape due to use-after-free in the Preferences: Backend component. Fixed in Thunderbird 157 and Firefox 157.
- CVE-2026-100800Critical
Sandbox escape due to use-after-free in the Disability Access APIs component. Fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.
- CVE-2026-100794Critical
Vulnerability allows sandbox escape due to incorrect boundary conditions in the Internationalization component. It was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
Original NVD description (English source)
Sandbox escape in the Profile Backup component. This vulnerability was fixed in Firefox 150.0.3, Firefox ESR 115.36, Firefox ESR 140.11, and Thunderbird 140.11.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS