CVE-2026-100828

Analyzed Analyzed - Analysis Complete

Mitigation Bypass in Firefox ESR and Firefox

Publication date: 2026-09-29

Last updated on: 2026-10-13

Assigner: Mozilla Corporation

Description

Mitigation bypass in the Bookmarks & History component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-09-29

Last Modified

2026-10-13

Generated

2026-10-19

AI Q&A

2026-09-29

EPSS Evaluated

2026-10-18

NVD

CVE-2026-100828

EUVD

EUVD-2026-88806

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 153.4.0 (exc)
mozilla	firefox	From 154.0.0 (inc) to 157.0.0 (exc)
mozilla	thunderbird	to 153.4.0 (exc)
mozilla	thunderbird	From 154.0 (inc) to 157.0 (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 Bookmarks & History component of Firefox. It allows attackers to bypass certain security measures that were meant to protect user data stored in these components.

Detection Guidance

Detection requires checking Firefox version. Run 'firefox --version' on Linux/macOS or check 'Help > About Firefox' in the GUI. If using ESR, verify version is 153.4 or higher. If using standard Firefox, ensure version is 157 or higher.

Impact Analysis

An attacker could exploit this to access or manipulate your bookmarks or browsing history without proper authorization. This might lead to privacy breaches or unauthorized tracking of your activities.

Compliance Impact

The provided CVE data does not specify how this vulnerability impacts compliance with standards like GDPR or HIPAA. Without additional context on the nature of the mitigation bypass or affected data types, its compliance implications cannot be determined.

Mitigation Strategies

Update Firefox to ESR 153.4 or Firefox 157 or later immediately. Disable the Bookmarks & History component if updates are not possible. Monitor Mozilla security advisories for further guidance.

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