CVE-2026-0891
Memory Corruption in Firefox and Thunderbird Enables Code Execution
Publication date: 2026-01-13
Last updated on: 2026-04-13
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 147 (exc) |
| mozilla | firefox | to 140.7 (exc) |
| mozilla | thunderbird | 146 |
| mozilla | thunderbird | to 140.7 (exc) |
| mozilla | firefox_esr | to 140.7 (exc) |
| mozilla | firefox_esr | 140.7 |
Helpful Resources
Exploitability
| 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
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability involves memory safety bugs in Firefox ESR 140.6, Thunderbird ESR 140.6, Firefox 146, and Thunderbird 146. Some of these bugs show evidence of memory corruption and could potentially be exploited to run arbitrary code. It affects Firefox versions below 147 and Firefox ESR versions below 140.7.
How can this vulnerability impact me? :
The vulnerability can lead to severe impacts including the possibility for attackers to execute arbitrary code remotely, which can compromise the confidentiality, integrity, and availability of your system. This could allow unauthorized actions within the browser environment, potentially leading to data loss, system compromise, or further exploitation.
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, you should update Firefox to version 147 or later, and Firefox ESR to version 140.7 or later, as these versions include fixes for the memory safety bugs and other related security issues. [2]