CVE-2026-88149

Undergoing Analysis Undergoing Analysis - In Progress

Double Free in Windows Ancillary Function Driver for WinSock

Publication date: 2026-10-13

Last updated on: 2026-10-16

Assigner: Microsoft Corporation

Description

Double free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-10-13

Last Modified

2026-10-16

Generated

2026-10-19

AI Q&A

2026-10-14

EPSS Evaluated

2026-10-18

NVD

CVE-2026-88149

EUVD

EUVD-2026-100102

Affected Vendors & Products

Vendor	Product	Version / Range
Microsoft	Windows	10 Version 1607 10.0.14393.0
Microsoft	Windows	10 Version 1809 10.0.17763.0
Microsoft	Windows	10 Version 21H2 10.0.19044.0
Microsoft	Windows	10 Version 22H2 10.0.19045.0
Microsoft	Windows	11 version 23H2 10.0.22631.0
Microsoft	Windows	11 Version 23H2 10.0.22631.0
Microsoft	Windows	11 Version 24H2 10.0.26100.0
Microsoft	Windows	11 Version 25H2 10.0.26200.0
Microsoft	Windows	11 version 26H1 10.0.28000.0
Microsoft	Windows	11 Version 26H2 10.0.26300.0
Microsoft	Windows	Server 2012 6.2.9200.0
Microsoft	Windows	Server 2012 (Server Core installation) 6.2.9200.0
Microsoft	Windows	Server 2012 R2 6.3.9600.0
Microsoft	Windows	Server 2012 R2 (Server Core installation) 6.3.9600.0
Microsoft	Windows	Server 2016 10.0.14393.0
Microsoft	Windows	Server 2016 (Server Core installation) 10.0.14393.0
Microsoft	Windows	Server 2019 10.0.17763.0
Microsoft	Windows	Server 2019 (Server Core installation) 10.0.17763.0
Microsoft	Windows	Server 2022 10.0.20348.0
Microsoft	Windows	Server 2025 10.0.26100.0
Microsoft	Windows	Server 2025 (Server Core installation) 10.0.26100.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-415	The product calls free() twice on the same memory address.

Attack-Flow Graph

Executive Summary

This vulnerability is a double free issue in the Windows Ancillary Function Driver for WinSock. A double free occurs when memory is freed twice, which can lead to memory corruption and potential arbitrary code execution. An authorized attacker could exploit this to elevate their privileges locally on an affected system.

Detection Guidance

Detection typically requires analyzing system logs for unusual activity in the Windows Ancillary Function Driver for WinSock. Check for crashes or memory corruption events in Event Viewer under Windows Logs > System. Use Process Monitor to monitor afd.sys for unexpected behavior. Microsoft Defender for Endpoint can also detect exploitation attempts.

Impact Analysis

If exploited, this vulnerability allows an attacker with local access to gain higher privileges on your system. This could enable them to install programs, view or delete data, or create new accounts with full user rights. Systems running vulnerable Windows versions are at risk.

Compliance Impact

This vulnerability allows local privilege escalation, which could enable unauthorized access to sensitive data or systems. This may violate compliance requirements under GDPR (data protection) and HIPAA (healthcare data) by exposing personal or protected health information.

Mitigation Strategies

Apply the latest security updates from Microsoft to patch the Windows Ancillary Function Driver for WinSock vulnerability. Monitor Microsoft's security advisories for updates and install them promptly.

Hi! I’m here to help you understand CVE-2026-88149. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70