CVE-2026-6755

Mitigation bypass in the DOM: postMessage component

Medium · published April 21, 2026

CVSS v3.1
6.5
EPSS
0%
Percentile
15.2
In the wild
Unconfirmed
What it is

Mitigation bypass in the DOM: postMessage component. This vulnerability was fixed in Firefox 150 and Thunderbird 150.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00248 · 15.2th percentile
Published
2026-04-21T12:40Z
EPSS history
Timeline
  • 21 APR 12:40Z
    Mitigation bypass in the DOM: postMessage component
    cvelistv5