CVE-2026-16399

Site isolation issue in the DOM: Navigation component

High · published July 21, 2026

CVSS v3.1
7.5
EPSS
0%
Percentile
3.8
In the wild
Unconfirmed
What it is

Site isolation issue in the DOM: Navigation component. This vulnerability was fixed in Firefox 153 and Thunderbird 153.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00149 · 3.8th percentile
Published
2026-07-21T12:38Z
EPSS history
Timeline
  • 21 JUL 12:38Z
    Site isolation issue in the DOM: Navigation component
    cvelistv5