CVE-2026-6759

Received Received - Intake

Use-After-Free in Firefox Cocoa Widget Causes Potential Crash

Publication date: 2026-04-21

Last updated on: 2026-04-22

Assigner: Mozilla Corporation

Description

Use-after-free in the Widget: Cocoa component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-04-21

Last Modified

2026-04-22

Generated

2026-07-06

AI Q&A

2026-04-21

EPSS Evaluated

2026-07-05

NVD

CVE-2026-6759

EUVD

EUVD-2026-24100

Affected Vendors & Products

Vendor	Product	Version / Range
mozilla	firefox	to 150.0 (exc)
mozilla	firefox	to 140.10.0 (exc)
mozilla	thunderbird	From 140.0 (inc) to 140.10.0 (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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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

Impact Analysis

This vulnerability is a use-after-free issue in the Widget: Cocoa component of Mozilla Firefox. Such vulnerabilities can potentially lead to application crashes, unexpected behavior, or exploitation by attackers to execute arbitrary code or cause denial of service.

It was fixed in Firefox 150 and Firefox ESR 140.10, so using these or later versions mitigates the risk.

Executive Summary

This vulnerability is a use-after-free issue in the Widget: Cocoa component of Mozilla Firefox. A use-after-free vulnerability occurs when a program continues to use a pointer after the memory it points to has been freed, which can lead to unexpected behavior or security risks.

This specific vulnerability was addressed and fixed in Firefox version 150 and Firefox ESR 140.10.

Mitigation Strategies

To mitigate this use-after-free vulnerability in the Widget: Cocoa component, you should update your Firefox browser to version 150 or later, or Firefox ESR to version 140.10 or later, where the issue has been fixed.

Hi! I’m here to help you understand CVE-2026-6759. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70