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 affects Firefox < 148, Firefox ESR < 115.33, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.