CVE-2026-68820

Microsoft Windows Ancillary Function Driver for WinSock

score 85Known exploited · added 2026-08-11Public PoC ×4watchlist: microsoft

Summary

Microsoft Windows Ancillary Function Driver for WinSock Use-After-Free Vulnerability

Microsoft Windows Ancillary Function Driver for WinSock contains a use-after-free vulnerability that allows an authorized attacker to elevate privileges locally.

Published 2026-08-11 · first seen here 2026-10-10

CISA required action (due 2026-08-25): Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Analysis & write-ups

No technical write-up from a research team yet. Contact Zero checks Unit 42, Google/Mandiant, Microsoft, Talos, CrowdStrike, Rapid7, watchTowr and others several times a day, plus NVD and CISA reference links.

Exploit availability

Public exploit code lowers the bar for attackers, so prioritise patching and hunting. These repositories are unverified. Fake PoCs that contain malware are common, so never run them outside an isolated lab.

HORKimhab/CVE-2026-68820 · ★1 · created 2026-08-13
ubitquity/Windows-WinSock-UAF-Mitigation · ★1 · created 2026-08-15
fevar54/CVE-2026-68820-Mitigation-PoC- · ★1 · created 2026-08-24
maxprog-svg/CVE-2026-68820_Mass_Exploit · ★0 · created 2026-08-25

Where it shows in your logs

Windows or Active Directory · Memory corruption (overflow, use-after-free) high confidence

What to look for

Crashes or restarts of the vulnerable process (Windows Error Reporting, core dumps), especially repeated ones
The vulnerable process spawning children it never normally starts
Processes running as SYSTEM whose parent is a normal user process
New local or domain admin accounts, or users added to privileged groups
Unusual logons (type 3 or 10) to servers right before suspicious processes start

Data sources

Process creation · ATT&CK DS0009 Process Creation

Sentinel: DeviceProcessEventsSecurityEvent (4688)Sysmon Event ID 1_Im_ProcessCreate
Splunk: Endpoint.ProcessesXmlWinEventLog:Microsoft-Windows-Sysmon/OperationalWinEventLog:Security (4688)
CrowdStrike: ProcessRollup2SyntheticProcessRollup2

Authentication and sessions · ATT&CK DS0028 Logon Session Creation / DS0002 User Account Authentication

Sentinel: SigninLogsSecurityEvent (4624, 4625, 4648)DeviceLogonEventsIdentityLogonEvents_Im_Authentication
Splunk: Authentication.Authenticationpan:globalprotectVPN sourcetypes
CrowdStrike: UserLogonUserLogonFailed2Falcon Identity Protection events

Account and group changes · ATT&CK DS0002 User Account Creation / Modification

Sentinel: SecurityEvent (4720, 4728, 4732, 4756)AuditLogsIdentityDirectoryEvents
Splunk: Change.All_Changes (Account_Management)WinEventLog:Security (4720, 4732)
CrowdStrike: UserAccountCreatedUserAccountAddedToGroup

A generic baseline worked out from the product type and weakness (CWE-416), not a detection. Check table and field names against your environment. Hunt queries for Sigma, Splunk, Sentinel and CrowdStrike are coming.