CVE-2026-2778

Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component

Critical · published February 24, 2026

CVSS v3.1
10.0
EPSS
1%
Percentile
52.8
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
10.0 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00704 · 52.8th percentile
Published
2026-02-24T13:33Z
EPSS history
Timeline
  • 24 FEB 13:33Z
    Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component
    cvelistv5