CVE-2026-74957

Analyzed Analyzed - Analysis Complete

Mitigation Bypass in Firefox Safe Browsing

Publication date: 2026-08-18

Last updated on: 2026-08-24

Assigner: Mozilla Corporation

Description

Mitigation bypass in the Safe Browsing component. This vulnerability was fixed in Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-08-18

Last Modified

2026-08-24

Generated

2026-09-07

AI Q&A

2026-08-18

EPSS Evaluated

2026-09-06

NVD

CVE-2026-74957

EUVD

EUVD-2026-60757

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	From 141.0 (inc) to 153.1.0 (exc)
mozilla	thunderbird	From 141.0 (inc) to 153.1.0 (exc)
mozilla	thunderbird	to 140.14.0 (exc)
mozilla	firefox	to 140.14.0 (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 is a mitigation bypass vulnerability in Firefox's Safe Browsing component. It allows attackers to evade security protections designed to block malicious websites or downloads. The issue was patched in Firefox 154 and specific Firefox ESR versions.

Detection Guidance

Detection requires checking Firefox, Firefox ESR, or Thunderbird versions. Compare installed versions against fixed releases: Firefox 154, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, or Thunderbird 153.1. Use commands like 'firefox --version' or 'thunderbird --version' to check versions.

Impact Analysis

If exploited, this vulnerability could allow malicious actors to bypass protections that prevent access to harmful websites or downloads. This increases the risk of malware infections, phishing attacks, or other cyber threats for users.

Compliance Impact

The provided CVE data does not specify how this vulnerability affects compliance with standards like GDPR or HIPAA. The description focuses on mitigation bypass in the Safe Browsing component without detailing regulatory impacts.

Mitigation Strategies

Update Firefox to version 154 or later, Firefox ESR to version 140.14 or later, or Firefox ESR to version 153.1 or later to apply the fixed Safe Browsing component.

Hi! I’m here to help you understand CVE-2026-74957. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70