CVE-2026-6784
Memory Corruption in Firefox and Thunderbird 149 Enables Code Execution
Publication date: 2026-04-21
Last updated on: 2026-04-29
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 | thunderbird | to 150.0 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-125 | The product reads data past the end, or before the beginning, of the intended buffer. |
| CWE-787 | The product writes data past the end, or before the beginning, of the intended buffer. |
| 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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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 involves memory safety bugs found in Firefox 149 and Thunderbird 149. Some of these bugs showed signs of memory corruption, which means that with enough effort, an attacker could potentially exploit them to run arbitrary code on the affected systems. The issue was addressed and fixed in Firefox 150.
How can this vulnerability impact me? :
If exploited, this vulnerability could allow an attacker to execute arbitrary code on your system through Firefox 149 or Thunderbird 149. This could lead to unauthorized actions, data compromise, or system control by the attacker.
What immediate steps should I take to mitigate this vulnerability?
The vulnerability was fixed in Firefox 150. Immediate mitigation involves updating Firefox and Thunderbird to version 150 or later to address the memory safety bugs.