CVE-2026-2777

Privilege escalation in the Messaging System component

Critical · published February 24, 2026

CVSS v3.1
9.8
EPSS
1%
Percentile
50.6
In the wild
Unconfirmed
What it is

Privilege escalation in the Messaging System component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

The record
Technical detail
CVSS v3.1
9.8 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00651 · 50.6th percentile
Published
2026-02-24T13:33Z
EPSS history
Timeline
  • 24 FEB 13:33Z
    Privilege escalation in the Messaging System component
    cvelistv5