CVE-2026-8949
Integer Overflow in Firefox Widget Win32 Component
Publication date: 2026-05-19
Last updated on: 2026-05-20
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 151.0.0 (exc) |
| mozilla | firefox | to 140.11.0 (exc) |
| mozilla | thunderbird | to 151.0.0 (exc) |
| mozilla | thunderbird | to 140.11 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-190 | The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number. |
Attack-Flow Graph
AI Powered Q&A
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
There is no information provided in the available context or resources about how the integer overflow vulnerability in the Widget: Win32 component (CVE-2026-8949) affects compliance with common standards and regulations such as GDPR or HIPAA.
How can this vulnerability impact me? :
This vulnerability is an integer overflow in the Widget: Win32 component of Mozilla Firefox. It has a CVSS v3.1 base score of 7.5, indicating a high severity. The attack vector is network-based with low attack complexity and no privileges or user interaction required. While it does not impact confidentiality or integrity, it has a high impact on availability, meaning it can cause denial of service or crash the application.
Can you explain this vulnerability to me?
This vulnerability is an integer overflow in the Widget: Win32 component of Mozilla Firefox. An integer overflow occurs when an arithmetic operation attempts to create a numeric value that is outside the range that can be represented with a given number of bits, potentially leading to unexpected behavior or security issues.
This specific issue was addressed and fixed in Firefox version 151 and Firefox ESR 140.11.
What immediate steps should I take to mitigate this vulnerability?
The vulnerability was fixed in Firefox 151 and Firefox ESR 140.11. Immediate mitigation steps include updating your Firefox or Firefox ESR browsers to these versions or later.