CVE-2026-84123

Analyzed Analyzed - Analysis Complete

Privilege Escalation in Firefox via WebGPU Use-After-Free

Publication date: 2026-09-01

Last updated on: 2026-09-02

Assigner: Mozilla Corporation

Description

Privilege escalation due to use-after-free in the Graphics: WebGPU component. This vulnerability was fixed in Firefox 155, Firefox ESR 153.2, Thunderbird 155, and Thunderbird 153.2.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-09-01

Last Modified

2026-09-02

Generated

2026-09-21

AI Q&A

2026-09-01

EPSS Evaluated

2026-09-20

NVD

CVE-2026-84123

EUVD

EUVD-2026-69072

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 153.2.0 (exc)
mozilla	firefox	From 154.0.0 (inc) to 155.0.0 (exc)
mozilla	thunderbird	to 153.2.0 (exc)
mozilla	thunderbird	From 154.0 (inc) to 155.0 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-416	The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Attack-Flow Graph

Executive Summary

This is a privilege escalation vulnerability caused by a use-after-free error in the Graphics: WebGPU component of Firefox. A use-after-free occurs when a program continues to use memory after it has been freed, potentially allowing attackers to execute arbitrary code or escalate privileges.

Detection Guidance

Detection requires checking Firefox version. If using Firefox <155 or Firefox ESR <153.2, the system is vulnerable. Update immediately to patched versions.

Impact Analysis

If exploited, this vulnerability could allow an attacker to gain elevated privileges on your system, potentially leading to unauthorized access, data theft, or installation of malicious software. Users of affected Firefox versions are at risk until they update to Firefox 155 or Firefox ESR 153.2.

Compliance Impact

The vulnerability allows privilege escalation and potential unauthorized access to sensitive data due to a use-after-free flaw in the Graphics: WebGPU component. This could lead to data breaches or unauthorized modifications, which may violate GDPR's data protection requirements or HIPAA's safeguards for protected health information if exploited.

Mitigation Strategies

Update Firefox to version 155 or later and Firefox ESR to version 153.2 or later to address the use-after-free vulnerability in Graphics: WebGPU.

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