CVE-2026-2778

CriticalCVSS 10.0

Published: 24/02/2026(UTC)Updated: 15/07/2026(UTC)Translated: 16/07/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.48%

38th 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 could exploit this vulnerability to escape the sandbox, potentially leading to arbitrary code execution within the browser or mail client context.

Recommendation

Immediately update Firefox to version 148 or later (or the appropriate ESR version) and 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.