CVE-2026-16377

Mitigation bypass in the PDF Viewer component

Critical · published July 21, 2026

CVSS v3.1
9.8
EPSS
0%
Percentile
31.6
In the wild
Unconfirmed
What it is

Mitigation bypass in the PDF Viewer component. This vulnerability was fixed in Firefox 153, Firefox ESR 140.13, Thunderbird 153, and Thunderbird 140.13.

The record
Technical detail
CVSS v3.1
9.8 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00387 · 31.6th percentile
Published
2026-07-21T12:37Z
EPSS history
Timeline
  • 21 JUL 12:37Z
    Mitigation bypass in the PDF Viewer component
    cvelistv5