---
title: "CVE-2026-68820: Microsoft Windows Ancillary Function Driver for WinSock Use-After-Free Vulnerability"
url: https://erroneo.us/security/cve/CVE-2026-68820/
description: "CVE-2026-68820 (Microsoft Windows Ancillary Function Driver for WinSock): Exploited in the wild (CISA KEV). Use after free in Windows Ancillary Function…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-08-11
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-68820"
kev: true
cvss: 7
epss: 0.00332
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Microsoft Windows Ancillary Function Driver for WinSock. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-08-11, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-08-25 ; treat that as the outer limit, not the target.
- EPSS 0.3% , percentile 25: FIRST’s model estimates a 0.3% chance of exploitation activity in the next 30 days, higher than 25% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs local access needed. Lower urgency for most teams unless an attacker could already run code on the machine.
- Editorial verdict: Patch this week. Windows AFD.sys CVE-2026-68820: Exploited Zero-Day EoP — A local bug, but a real zero-day: North Korea's Lazarus group used it to load a kernel rootkit, so any Windows host still missing the August 2026 or later cumulative update should be patched this week.

## What it is

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

## Affected products (CVE record)

- Microsoft Windows 10 Version 1607: 10.0.14393.0 < 10.0.14393.9418
- Microsoft Windows 10 Version 1809: 10.0.17763.0 < 10.0.17763.9121
- Microsoft Windows 10 Version 21H2: 10.0.19044.0 < 10.0.19044.7663
- Microsoft Windows 10 Version 22H2: 10.0.19045.0 < 10.0.19045.7663
- Microsoft Windows 11 version 23H2: 10.0.22631.0 < 10.0.22631.7517
- Microsoft Windows 11 Version 23H2: 10.0.22631.0 < 10.0.22631.7517
- Microsoft Windows 11 Version 24H2: 10.0.26100.0 < 10.0.26100.9168
- Microsoft Windows 11 Version 25H2: 10.0.26200.0 < 10.0.26200.9168
- Microsoft Windows 11 version 26H1: 10.0.28000.0 < 10.0.28000.2704
- Microsoft Windows Server 2012: 6.2.9200.0 < 6.2.9200.26280

## Severity

- microsoft CVSS 3.1: 7 `CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C`

## Exploitation

- CISA KEV: added 2026-08-11; federal due date 2026-08-25. Known ransomware use: Unknown.
- 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.
- CISA SSVC assessment: exploitation active , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.33% probability of exploitation activity in the next 30 days; percentile 25.

## Sources

- [Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68820)
- [Listed in CISA KEV notes (portal.msrc.microsoft.com)](https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-68820)
- [CVE.org record CVE-2026-68820](https://www.cve.org/CVERecord?id=CVE-2026-68820)
- [NVD entry CVE-2026-68820](https://nvd.nist.gov/vuln/detail/CVE-2026-68820)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-68820)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk)
- [Listed in CISA KEV notes (cisa.gov)](https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk)

---
Source page: https://erroneo.us/security/cve/CVE-2026-68820/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt