CVEs / CVE-2026-68820
CVE-2026-68820: Microsoft Windows Ancillary Function Driver for WinSock Use-After-Free Vulnerability
- Known exploited in the CISA KEV catalog since 11 Aug 2026
- high 7 CVSS 3.1 (from the CNA)
- EPSS 8.56% chance of exploitation in the next 30 days, higher than 95% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
Microsoft Windows Ancillary Function Driver for WinSock contains a use-after-free vulnerability that allows an authorized attacker to elevate privileges locally.
Description
Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Microsoft Windows 10 Version 1607 | from 10.0.14393.0, before 10.0.14393.9418 | 10.0.14393.9418 |
| Microsoft Windows 10 Version 1809 | from 10.0.17763.0, before 10.0.17763.9121 | 10.0.17763.9121 |
| Microsoft Windows 10 Version 21H2 | from 10.0.19044.0, before 10.0.19044.7663 | 10.0.19044.7663 |
| Microsoft Windows 10 Version 22H2 | from 10.0.19045.0, before 10.0.19045.7663 | 10.0.19045.7663 |
| Microsoft Windows 11 version 23H2 | from 10.0.22631.0, before 10.0.22631.7517 | 10.0.22631.7517 |
| Microsoft Windows 11 Version 23H2 | from 10.0.22631.0, before 10.0.22631.7517 | 10.0.22631.7517 |
| Microsoft Windows 11 Version 24H2 | from 10.0.26100.0, before 10.0.26100.9168 | 10.0.26100.9168 |
| Microsoft Windows 11 Version 25H2 | from 10.0.26200.0, before 10.0.26200.9168 | 10.0.26200.9168 |
| Microsoft Windows 11 version 26H1 | from 10.0.28000.0, before 10.0.28000.2704 | 10.0.28000.2704 |
| Microsoft Windows Server 2012 | from 6.2.9200.0, before 6.2.9200.26280 | 6.2.9200.26280 |
| Microsoft Windows Server 2012 (Server Core installation) | from 6.2.9200.0, before 6.2.9200.26280 | 6.2.9200.26280 |
| Microsoft Windows Server 2012 R2 | from 6.3.9600.0, before 6.3.9600.23338 | 6.3.9600.23338 |
| Microsoft Windows Server 2012 R2 (Server Core installation) | from 6.3.9600.0, before 6.3.9600.23338 | 6.3.9600.23338 |
| Microsoft Windows Server 2016 | from 10.0.14393.0, before 10.0.14393.9418 | 10.0.14393.9418 |
| Microsoft Windows Server 2016 (Server Core installation) | from 10.0.14393.0, before 10.0.14393.9418 | 10.0.14393.9418 |
| Microsoft Windows Server 2019 | from 10.0.17763.0, before 10.0.17763.9121 | 10.0.17763.9121 |
| Microsoft Windows Server 2019 (Server Core installation) | from 10.0.17763.0, before 10.0.17763.9121 | 10.0.17763.9121 |
| Microsoft Windows Server 2022 | from 10.0.20348.0, before 10.0.20348.5499 | 10.0.20348.5499 |
| Microsoft Windows Server 2025 | from 10.0.26100.0, before 10.0.26100.33296 | 10.0.26100.33296 |
| Microsoft Windows Server 2025 (Server Core installation) | from 10.0.26100.0, before 10.0.26100.33296 | 10.0.26100.33296 |
Exploitation
| In CISA KEV since | 11 Aug 2026 |
|---|---|
| Due date for US federal agencies | 25 Aug 2026 |
| Used in ransomware campaigns | Unknown |
| 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. |
Severity
| CVSS 3.1 | 7 highCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:HScored by the CNA ([email protected]) |
|---|---|
| Weakness | CWE-416 |
References
- CVE-2026-68820 on NVD
- CVE-2026-68820 in the CISA KEV catalog
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-68820 (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk (cited by CISA)
- https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk (cited by CISA)
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68820 Patch, Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-68820 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.