CVE-2026-100820
Received Received - Intake

Privilege Escalation in Firefox Address Bar

Publication date: 2026-09-29

Last updated on: 2026-09-29

Assigner: Mozilla Corporation

Description
Privilege escalation in the Address Bar component. This vulnerability was fixed in Firefox ESR 153.4, Firefox 157, and Firefox ESR 140.17.

CVSS Scores

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Meta Information

Published
2026-09-29
Last Modified
2026-09-29
Generated
2026-09-29
AI Q&A
2026-09-29
EPSS Evaluated
N/A
NVD
CVE-2026-100820
EUVD
EUVD-2026-88799

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
mozilla firefox to 153.4 (inc)
mozilla firefox 157
mozilla firefox to 140.17 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-269 The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.

Attack-Flow Graph

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Executive Summary

This is a privilege escalation vulnerability in Firefox's Address Bar component. It allows an attacker to gain higher privileges than intended, potentially executing unauthorized actions.

Detection Guidance

This vulnerability affects the Address Bar component in Firefox browsers. To detect it, check the installed Firefox version against the fixed versions: Firefox ESR 153.4, Firefox 157, or Firefox ESR 140.17. Use commands like 'firefox --version' or check 'about:support' in Firefox to verify the version.

Impact Analysis

If exploited, this vulnerability could let attackers take control of your browser session, steal sensitive data, or install malicious software without your knowledge.

Compliance Impact

The vulnerability allows privilege escalation through the Address Bar component, which could lead to unauthorized access or data manipulation. This may impact compliance with GDPR by risking unauthorized data access or processing, and with HIPAA by potentially exposing protected health information. The high CVSS score (8.8) indicates significant risk to confidentiality, integrity, and availability of data.

Mitigation Strategies

Update Firefox ESR to version 153.4 or later, Firefox to version 157 or later, or Firefox ESR to version 140.17 or later to address the privilege escalation in the Address Bar component.

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