CVE-2026-74953

Analyzed Analyzed - Analysis Complete

Privilege Escalation in Firefox Networking Cookies

Publication date: 2026-08-18

Last updated on: 2026-08-21

Assigner: Mozilla Corporation

Description

Privilege escalation in the Networking: Cookies 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

2026-08-21

Generated

2026-09-07

AI Q&A

2026-08-18

EPSS Evaluated

2026-09-06

NVD

CVE-2026-74953

EUVD

EUVD-2026-60756

Affected Vendors & Products

Vendor	Product	Version / Range
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)
mozilla	firefox	From 141.0.0 (inc) to 153.1.0 (exc)

Helpful Resources

Exploitability

CWE

KEV

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

Executive Summary

This is a privilege escalation vulnerability in the Networking: Cookies component of Firefox browsers. It allows an attacker to gain higher privileges than intended, potentially leading to unauthorized access or control.

Detection Guidance

This vulnerability is specific to Firefox versions before 154, Firefox ESR 140.14, and Firefox ESR 153.1. To detect it, check installed Firefox versions using commands like 'firefox --version' or 'dpkg -l firefox' on Linux. Compare against patched versions.

Impact Analysis

If exploited, this vulnerability could allow attackers to escalate their privileges on your system, potentially accessing sensitive data or performing unauthorized actions. Users of affected Firefox versions should update to the patched versions immediately.

Compliance Impact

The provided CVE data does not specify direct impacts on compliance with GDPR, HIPAA, or other standards. However, privilege escalation vulnerabilities like this can potentially lead to unauthorized access to sensitive data, which may violate compliance requirements under GDPR (data protection) and HIPAA (protected health information).

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 address the privilege escalation in the Networking: Cookies component.

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