CVE-2026-6754
Use-After-Free in Firefox JavaScript Engine Enables Exploits
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 115.35.0 (exc) |
| mozilla | firefox | From 140.0 (inc) to 140.10.0 (exc) |
| mozilla | thunderbird | 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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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 JavaScript Engine 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 exploitation.
The issue was addressed and fixed in Firefox version 150, Firefox ESR 115.35, and Firefox ESR 140.10.
How can this vulnerability impact me? :
Exploitation of a use-after-free vulnerability in the JavaScript Engine could potentially allow an attacker to execute arbitrary code, cause a crash, or manipulate the behavior of the browser. This could lead to unauthorized actions or compromise of the system running the affected Firefox versions.
What immediate steps should I take to mitigate this vulnerability?
To mitigate this use-after-free vulnerability in the JavaScript Engine component, update your Firefox browsers to the fixed versions: Firefox 150, Firefox ESR 115.35, or Firefox ESR 140.10.