CVE-2026-16396

Privilege escalation in WebExtensions

High · published July 21, 2026

CVSS v3.1
8.8
EPSS
0%
Percentile
14.3
In the wild
Unconfirmed
What it is

Privilege escalation in WebExtensions. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

The record
Technical detail
CVSS v3.1
8.8 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00241 · 14.3th percentile
Published
2026-07-21T12:38Z
EPSS history
Timeline
  • 21 JUL 12:38Z
    Privilege escalation in WebExtensions
    cvelistv5