CVE-2026-2778
CriticalCVSS 10.0Exploitation Probability (EPSS)
Low risk38th percentile - higher than 38% of all known CVEs
Summary
A sandbox escape vulnerability due to incorrect boundary conditions in the DOM: Core & HTML component. This flaw was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
Risk Assessment
An attacker can exploit this vulnerability to escape the browser sandbox, potentially leading to arbitrary code execution on the underlying operating system and full device compromise.
Recommendation
Immediately update Firefox to version 148 or later, and ESR versions to 115.33 or 140.8. Also update Thunderbird to version 148 or 140.8.
Original NVD description (English source)
Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.