SB2025101487 - Multiple vulnerabilities in Microsoft Windows Ancillary Function Driver for WinSock

Description

This security bulletin contains information about 2 vulnerabilities.

1) Heap-based buffer overflow (CVE-ID: CVE-2025-59242)

CWE-ID: CWE-122 - Heap-based Buffer Overflow

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error in Windows Ancillary Function Driver for WinSock. A local user can pass specially crafted data to the application, trigger a heap-based buffer overflow and execute arbitrary code on the target system with elevated privileges.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

2) Improper access control (CVE-ID: CVE-2025-58714)

CWE-ID: CWE-284 - Improper Access Control

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to gain unauthorized access to otherwise restricted functionality.

The vulnerability exists due to improper access restrictions in Windows Ancillary Function Driver for WinSock. A local user can bypass implemented security restrictions and gain elevated privileges on the target system.

Remediation

Install update from vendor's website.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-59242
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-58714