CVERadar
HIGH · CVSS 3.1 7CISA KEV · added 2026-08-11Public PoCEPSS 0.33% (p25)Threat level 50

CVE-2026-68820: Microsoft Windows Ancillary Function Driver for WinSock Use-After-Free Vulnerability

Microsoft · Windows Ancillary Function Driver for WinSock · NVD published 2026-08-11 · posted 2026-08-11 · last modified 2026-08-17

What it is

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

WeaknessCWE-416
CVSS vectorCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H (source: [email protected])
CISA due date2026-08-25 (for US federal agencies under BOD; a good deadline for everyone)
ATT&CK tacticsExecution

Exploitation evidence

First exploit evidence seen: 2026-08-11 (earliest date across the sources below).

Exploited in the wild

  • CISA KEV: listed since 2026-08-11. Source

Public exploit code

GitHub proof-of-concept repositories

4 public repositories from 4 accounts, first seen 2026-08-13. Most starred: ubitquity/Windows-WinSock-UAF-Mitigation (1 stars), view repository.

Verify before running: public PoCs can be malicious. Read the code and only run it in an isolated lab. A PoC means exploit code is public, not that this CVE is exploited in the wild.

Sources: CISA KEV · nomi-sec/PoC-in-GitHub.

Defend the Chain

The attack chain for CVE-2026-68820 laid across the MITRE ATT&CK Enterprise tactics. Solid cards come from the MITRE CTID KEV mappings; dashed cards are inferred by CVERadar from the CWE or description. Correct defences are real ATT&CK mitigations for that technique.

Threat level 50/100
Defender level 1 · 0 XP
Chain links broken: 0/1

Reconnaissance

Resource Development

Initial Access

Execution

Persistence

Privilege Escalation

Stealth

Defense Impairment

Credential Access

Discovery

Lateral Movement

Collection

Command and Control

Exfiltration

Impact

Pick a red technique card on the board, then choose the defence that stops it.

Defend against T1203 Exploitation for Client Execution Inferred

Inferred from CWE CWE-416

How to fix it

CISA required action

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. (source: CISA KEV)

Fixed versions

  • microsoft windows 10 1607: upgrade to 10.0.14393.9418 or later
  • microsoft windows 10 1809: upgrade to 10.0.17763.9115 or later
  • microsoft windows 10 21h2: upgrade to 10.0.19044.7663 or later
  • microsoft windows 10 22h2: upgrade to 10.0.19045.7663 or later
  • microsoft windows 11 23h2: upgrade to 10.0.22631.7517 or later
  • microsoft windows 11 24h2: upgrade to 10.0.26100.9106 or later
  • microsoft windows 11 25h2: upgrade to 10.0.26200.9106 or later
  • microsoft windows 11 26h1: upgrade to 10.0.28000.2704 or later
  • microsoft windows server 2016: upgrade to 10.0.14393.9418 or later
  • microsoft windows server 2019: upgrade to 10.0.17763.9115 or later
  • microsoft windows server 2022: upgrade to 10.0.20348.5440 or later
  • microsoft windows server 2025: upgrade to 10.0.26100.33222 or later

Derived from the NVD CPE configuration (versionEndExcluding / versionEndIncluding). Always confirm with the vendor advisory.

Vendor advisories and patches

MITRE ATT&CK mitigations for this chain

  • M1050 Exploit Protection (for T1203) : Security applications that look for behavior used during exploitation such as Windows Defender Exploit Guard (WDEG) and the Enhanced Mitigation Experience Toolkit (EMET) can be used to mitigate some exploitation behavior. Control flow integrity checking is another way to potentially identify and stop a software exploi
  • M1051 Update Software (for T1203) : Perform regular software updates to mitigate exploitation risk. Keeping software up-to-date with the latest security patches helps prevent adversaries from exploiting known vulnerabilities in client software, reducing the risk of successful attacks.
  • M1048 Application Isolation and Sandboxing (for T1203) : Browser sandboxes can be used to mitigate some of the impact of exploitation, but sandbox escapes may still exist. Other types of virtualization and application microsegmentation may also mitigate the impact of client-side exploitation. Risks of additional exploits and weaknesses in those systems may still exist.

Detection Generic guidance

  • Execution: Watch for the service process spawning shells or script interpreters (cmd.exe, powershell, sh, bash, python) via EDR process-tree rules.

Response checklist Generic guidance

  1. Inventory: find every instance of the affected product and version (include internet-facing and forgotten ones).
  2. Patch or mitigate per the vendor advisory; if you cannot patch, remove internet exposure or apply the vendor workaround.
  3. Assume compromise if the system was exposed before patching: hunt for the indicators in the advisory and review logs back to the disclosure date.
  4. Rotate credentials and secrets stored on or used by the affected system if compromise cannot be ruled out.

Sources