CVE-2026-74946

Analyzed Analyzed - Analysis Complete

Privilege Escalation in Firefox CanvasWebGL

Publication date: 2026-08-18

Last updated on: 2026-08-21

Assigner: Mozilla Corporation

Description

Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.

CVSS Scores

EPSS Scores

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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-2026-74946

EUVD

EUVD-2026-60753

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 115.39.0 (exc)
mozilla	firefox	From 116.0 (inc) to 140.14.0 (exc)
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)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-119	The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.

Attack-Flow Graph

Executive Summary

This is a privilege escalation vulnerability caused by incorrect boundary conditions in the Graphics: CanvasWebGL component of Firefox browsers. It allows attackers to gain elevated privileges beyond normal user access.

Detection Guidance

Detection requires checking Firefox version against patched releases. For Firefox, run: firefox --version. For ESR versions, check: firefox --version | grep ESR. Compare against Firefox 154, ESR 115.39, ESR 140.14, or ESR 153.1.

Impact Analysis

An attacker could exploit this to gain unauthorized access to sensitive data, install malware, or take control of your system. Users of affected Firefox versions are at risk until they update to patched versions.

Compliance Impact

The provided CVE data does not specify any direct impact on compliance with standards like GDPR or HIPAA. The vulnerability involves privilege escalation in the Graphics: CanvasWebGL component, which could potentially lead to unauthorized access or data exposure, but no explicit compliance implications are mentioned.

Mitigation Strategies

Update Firefox to version 154 or Firefox ESR to 115.39, 140.14, or 153.1. Disable CanvasWebGL if updates are not immediately possible by setting gfx.canvas.accelerated to false in about:config.

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