Main Vulnerability Database Vulnerabilities #VU146630

Input validation error in Mozilla Firefox and Firefox for Android - CVE-2026-84138

Published: September 1, 2026

Vulnerability identifier: #VU146630

CSH Severity: Low

CVSS v4: 4.6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-84138

CWE-ID: CWE-20

Exploitation vector: Remote access

Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to improper input validation in the PDF Viewer component when rendering a crafted PDF document. A remote attacker can supply a crafted PDF document to cause a denial of service.

User interaction is required to open a crafted PDF document.

Affected software

Mozilla Firefox
Firefox for Android

How to mitigate CVE-2026-84138

Install security update from vendor's website.

Mozilla Firefox - update to 155.0
Firefox for Android - update to 155.0

External References

Related Security Bulletins