CVE-2026-4691
Received
Received - Intake
Use-After-Free in Firefox CSS Parsing Enables Potential Exploits
Publication date: 2026-03-24
Last updated on: 2026-04-13
Assigner: Mozilla Corporation
Description
Description
Use-after-free in the CSS Parsing and Computation component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| mozilla | firefox | to 149.0 (exc) |
| mozilla | firefox | to 115.34.0 (exc) |
| mozilla | firefox | From 128.0 (inc) to 140.9.0 (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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is a use-after-free issue in the CSS Parsing and Computation component of Firefox. It affects versions of Firefox earlier than 149, Firefox ESR earlier than 115.34, and Firefox ESR earlier than 140.9.
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