CVE-2026-2778: firefox: thunderbird: Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component

Severity: Critical

CVSS Score: 10

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.