Use After Free Vulnerability in Windows Ancillary Function Driver by Microsoft
CVE-2026-33099

7HIGH

Key Information:

Vendor

Microsoft
Status
Windows 10 Version 1607
Windows 10 Version 1809
Windows 10 Version 21h2
Windows 10 Version 22h2
Vendor
CVE Published:
14 April 2026

What is CVE-2026-33099?

A use after free vulnerability in the Windows Ancillary Function Driver for WinSock could allow an attacker who has already gained access to the system to elevate their privileges. This occurs due to improper handling of memory, which may potentially be exploited by an authorized user to gain unauthorized access to critical system areas or perform malicious actions. It is crucial for users to ensure their systems are updated with the latest security patches to mitigate this risk.

Affected Version(s)

Windows 10 Version 1607 32-bit Systems 10.0.14393.0 < 10.0.14393.9060

Windows 10 Version 1809 32-bit Systems 10.0.17763.0 < 10.0.17763.8644

Windows 10 Version 21H2 32-bit Systems 10.0.19044.0 < 10.0.19044.7184

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE...
vendor-advisorypatch

CVSS V3.1

Score:
7
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
High
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.