CVE-2026-6759
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
Description
CVSS Scores
EPSS Scores
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Meta Information
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 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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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
AI Powered Q&A
Can you explain this vulnerability to me?
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.
What immediate steps should I take to mitigate this vulnerability?
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.
How can this vulnerability impact me? :
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.