CVE-2026-84128CWE-284broken-access-control

CVE-2026-84128

High · published September 1, 2026

CVSS v3.1
8.8
EPSS
0%
Percentile
37.0
In the wild
Unconfirmed
What it is

Privilege escalation in the WebDriver BiDi component. This vulnerability was fixed in Firefox 155 and Thunderbird 155.

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
0.00437 · 37.0th percentile
Weakness
CWE-284 · Improper Access Control
Published
2026-09-01T17:20Z
Affected products (2)
ProductVersionsFixed in
mozilla/firefox< 155.0.0155.0.0
mozilla/thunderbird< 155.0155.0
References (3)
https://bugzilla.mozilla.org/show_bug.cgi?id=2044280 · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-82/ · [email protected]https://www.mozilla.org/security/advisories/mfsa2026-86/ · [email protected]
EPSS history
Timeline
  • 03 SEP 03:32Z
    EPSS moved — → 0%
    epss
  • 01 SEP 12:18Z
    Privilege escalation in the WebDriver BiDi component
    cvelistv5