PT-2026-48002 · Microsoft · Windows Ancillary Function Driver For Winsock+1

CVE-2026-45638 · Published 2026-06-09 · Updated 2026-06-09

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions Windows Ancillary Function Driver for WinSock (affected versions not specified)

Description A use after free issue in the Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally. Use after free is a memory corruption flaw that occurs when an application continues to use a pointer after it has been freed, which can be exploited to execute arbitrary code or gain higher system permissions.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

DoS

RCE

Heap Based Buffer Overflow

Weakness Enumeration

CWE-122

Related Identifiers

BDU:2026-08481

CVE-2026-45638

Affected Products

Windows

Windows Ancillary Function Driver For Winsock

References · 6

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45638 · Vendor Advisory
• https://bdu.fstec.ru/vul/2026-08481 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-45638 · Security Note
• http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2026-45638 · Security Note
• https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2026-45638 · Vendor Advisory
• https://twitter.com/windowsforum/status/2064496828062556357 · Twitter Post