CVE-2026-16377

Analyzed Analyzed - Analysis Complete

Mitigation Bypass in Firefox PDF Viewer

Publication date: 2026-07-21

Last updated on: 2026-07-24

Assigner: Mozilla Corporation

Description

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

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-07-21

Last Modified

2026-07-24

Generated

2026-08-10

AI Q&A

2026-07-21

EPSS Evaluated

2026-08-09

NVD

CVE-2026-16377

EUVD

EUVD-2026-46213

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 153.0.0 (exc)
mozilla	firefox	to 140.13.0 (exc)
mozilla	thunderbird	to 140.13.0 (exc)
mozilla	thunderbird	From 141.0 (inc) to 153.0 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-693	The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.

Attack-Flow Graph

Executive Summary

This vulnerability is a mitigation bypass in the PDF Viewer component of Firefox. It allows attackers to bypass certain security measures that were meant to prevent exploitation. The issue was addressed in Firefox version 153 and Firefox ESR version 140.13.

Detection Guidance

Detection requires checking Firefox and Firefox ESR versions. If your version is below 153 for Firefox or 140.13 for ESR, the system is vulnerable. Use commands like 'firefox --version' or 'firefox-esr --version' to check installed versions.

Impact Analysis

If exploited, this vulnerability could allow attackers to bypass security restrictions, potentially leading to unauthorized access or execution of malicious code on your system. Users of affected Firefox versions should update immediately to mitigate the risk.

Compliance Impact

The provided CVE data does not specify how this vulnerability impacts compliance with standards like GDPR or HIPAA. The description only mentions a mitigation bypass in the PDF Viewer component without detailing potential compliance implications.

Mitigation Strategies

Update Firefox to version 153 or later and Firefox ESR to version 140.13 or later to address the mitigation bypass in the PDF Viewer component.

Hi! I’m here to help you understand CVE-2026-16377. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70