Microsoft Windows Ancillary Function Driver for WinSock Use-After-Free Vulnerability
Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
What happened
Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
CISA lists it as exploited, added 11 Aug 2026.
Does it affect you
Names Microsoft Windows Server. Enter the product and version you run to place it against the affected range the vendor published.
What to do
- Apply the vendor patch named in this advisory.
msrc.microsoft.com - 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.gov
CISA’s notes for this entry:
- portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-68820
- BOD 26-04: cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- Forensics Triage Requirements: cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk
- nvd.nist.gov/vuln/detail/CVE-2026-68820
Affected, as published to NVD
- ms-winserver
- Microsoft Windows Server: everything below 10.0.14393.9418
The record
- NVD status
- Analyzed
- Published
- 11 Aug 2026, last modified 16 Aug 2026 (NVD)
- Severity
- CVSS 3.1 base score 7.0, High — computed here from the vector; NVD states 7.0.
- Vector
- CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness
- CWE-416 Use After Free (NVD; names by MITRE)
- Exploitation
- Listed in CISA’s Known Exploited Vulnerabilities catalogue since 11 Aug 2026; federal remediation due 25 Aug 2026. CISA entry
- Exploit probability
- EPSS 6.2%, 93rd percentile — FIRST. FIRST EPSS
- Vendor
- Microsoft · Windows Ancillary Function Driver for WinSock (CISA)
References on the NVD record
- msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68820PatchVendor Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-68820US Government Resource
Sources
The verdict above is computed from the products and versions you entered and the affected ranges the vendor published to NVD. It does not inspect your environment, and this site never reports a product as unaffected: why.