CVE-2026-2777

29th percentile - higher than 29% of all known CVEs

A privilege escalation vulnerability exists in the Messaging System component of Firefox and Thunderbird. The flaw is fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

Privilege escalation could allow an attacker to gain unauthorized access to sensitive data or perform operations with elevated privileges, posing a serious risk to system confidentiality and integrity.

Immediately update Firefox to version 148 or later, and Thunderbird to version 148 or later. For ESR versions, apply Firefox ESR 115.33, Firefox ESR 140.8, or Thunderbird 140.8 accordingly.