Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
Priority LOW 36CWE-122Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Privilege escalation
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Microsoft. Impact type from Microsoft.
Summary
Heap-based buffer overflow in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00439 38th percentileScored 2026-11-07
Fix Fixed Microsoft: 14 updates
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Microsoft | Windows 10 Version 1607 | 10.0.14393.0 to before 10.0.14393.8868 | 10.0.14393.8868 | Patch available | CNA |
| Microsoft | Windows 10 Version 1809 | 10.0.17763.0 to before 10.0.17763.8389 | 10.0.17763.8389 | Patch available | CNA |
| Microsoft | Windows 10 Version 21H2 | 10.0.19044.0 to before 10.0.19044.6937 | 10.0.19044.6937 | Patch available | CNA |
| Microsoft | Windows 10 Version 22H2 | 10.0.19045.0 to before 10.0.19045.6937 | 10.0.19045.6937 | Patch available | CNA |
| Microsoft | Windows 11 version 22H3 | 10.0.22631.0 to before 10.0.22631.6649 | 10.0.22631.6649 | Patch available | CNA |
| Microsoft | Windows 11 Version 23H2 | 10.0.22631.0 to before 10.0.22631.6649 | 10.0.22631.6649 | Patch available | CNA |
| Microsoft | Windows 11 Version 24H2 | 10.0.26100.0 to before 10.0.26100.7840 | 10.0.26100.7840 | Patch available | CNA |
| Microsoft | Windows 11 Version 25H2 | 10.0.26200.0 to before 10.0.26200.7840 | 10.0.26200.7840 | Patch available | CNA |
| Microsoft | Windows 11 version 26H1 | 10.0.28000.0 to before 10.0.28000.1575 | 10.0.28000.1575 | Patch available | CNA |
| Microsoft | Windows 11 Version 26H1 | 10.0.28000.0 to before 10.0.28000.1575 | 10.0.28000.1575 | Patch available | CNA |
| Microsoft | Windows Server 2012 | 6.2.9200.0 to before 6.2.9200.25923 | 6.2.9200.25923 | Patch available | CNA |
| Microsoft | Windows Server 2012 (Server Core installation) | 6.2.9200.0 to before 6.2.9200.25923 | 6.2.9200.25923 | Patch available | CNA |
| Microsoft | Windows Server 2012 R2 | 6.3.9600.0 to before 6.3.9600.23022 | 6.3.9600.23022 | Patch available | CNA |
| Microsoft | Windows Server 2012 R2 (Server Core installation) | 6.3.9600.0 to before 6.3.9600.23022 | 6.3.9600.23022 | Patch available | CNA |
| Microsoft | Windows Server 2016 | 10.0.14393.0 to before 10.0.14393.8868 | 10.0.14393.8868 | Patch available | CNA |
| Microsoft | Windows Server 2016 (Server Core installation) | 10.0.14393.0 to before 10.0.14393.8868 | 10.0.14393.8868 | Patch available | CNA |
| Microsoft | Windows Server 2019 | 10.0.17763.0 to before 10.0.17763.8389 | 10.0.17763.8389 | Patch available | CNA |
| Microsoft | Windows Server 2019 (Server Core installation) | 10.0.17763.0 to before 10.0.17763.8389 | 10.0.17763.8389 | Patch available | CNA |
| Microsoft | Windows Server 2022 | 10.0.20348.0 to before 10.0.20348.4773 | 10.0.20348.4773 | Patch available | CNA |
| Microsoft | Windows Server 2022, 23H2 Edition (Server Core installation) | 10.0.25398.0 to before 10.0.25398.2149 | 10.0.25398.2149 | Patch available | CNA |
| Microsoft | Windows Server 2025 | 10.0.26100.0 to before 10.0.26100.32370 | 10.0.26100.32370 | Patch available | CNA |
| Microsoft | Windows Server 2025 (Server Core installation) | 10.0.26100.0 to before 10.0.26100.32370 | 10.0.26100.32370 | Patch available | CNA |
- Windows 10 Version 1607 VendorMicrosoft Affected 10.0.14393.0 to before 10.0.14393.8868 Fixed in 10.0.14393.8868 Patch available CNA
- Windows 10 Version 1809 VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.8389 Fixed in 10.0.17763.8389 Patch available CNA
- Windows 10 Version 21H2 VendorMicrosoft Affected 10.0.19044.0 to before 10.0.19044.6937 Fixed in 10.0.19044.6937 Patch available CNA
- Windows 10 Version 22H2 VendorMicrosoft Affected 10.0.19045.0 to before 10.0.19045.6937 Fixed in 10.0.19045.6937 Patch available CNA
- Windows 11 version 22H3 VendorMicrosoft Affected 10.0.22631.0 to before 10.0.22631.6649 Fixed in 10.0.22631.6649 Patch available CNA
- Windows 11 Version 23H2 VendorMicrosoft Affected 10.0.22631.0 to before 10.0.22631.6649 Fixed in 10.0.22631.6649 Patch available CNA
- Windows 11 Version 24H2 VendorMicrosoft Affected 10.0.26100.0 to before 10.0.26100.7840 Fixed in 10.0.26100.7840 Patch available CNA
- Windows 11 Version 25H2 VendorMicrosoft Affected 10.0.26200.0 to before 10.0.26200.7840 Fixed in 10.0.26200.7840 Patch available CNA
- Windows 11 version 26H1 VendorMicrosoft Affected 10.0.28000.0 to before 10.0.28000.1575 Fixed in 10.0.28000.1575 Patch available CNA
- Windows 11 Version 26H1 VendorMicrosoft Affected 10.0.28000.0 to before 10.0.28000.1575 Fixed in 10.0.28000.1575 Patch available CNA
- Windows Server 2012 VendorMicrosoft Affected 6.2.9200.0 to before 6.2.9200.25923 Fixed in 6.2.9200.25923 Patch available CNA
- Windows Server 2012 (Server Core installation) VendorMicrosoft Affected 6.2.9200.0 to before 6.2.9200.25923 Fixed in 6.2.9200.25923 Patch available CNA
- Windows Server 2012 R2 VendorMicrosoft Affected 6.3.9600.0 to before 6.3.9600.23022 Fixed in 6.3.9600.23022 Patch available CNA
- Windows Server 2012 R2 (Server Core installation) VendorMicrosoft Affected 6.3.9600.0 to before 6.3.9600.23022 Fixed in 6.3.9600.23022 Patch available CNA
- Windows Server 2016 VendorMicrosoft Affected 10.0.14393.0 to before 10.0.14393.8868 Fixed in 10.0.14393.8868 Patch available CNA
- Windows Server 2016 (Server Core installation) VendorMicrosoft Affected 10.0.14393.0 to before 10.0.14393.8868 Fixed in 10.0.14393.8868 Patch available CNA
- Windows Server 2019 VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.8389 Fixed in 10.0.17763.8389 Patch available CNA
- Windows Server 2019 (Server Core installation) VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.8389 Fixed in 10.0.17763.8389 Patch available CNA
- Windows Server 2022 VendorMicrosoft Affected 10.0.20348.0 to before 10.0.20348.4773 Fixed in 10.0.20348.4773 Patch available CNA
- Windows Server 2022, 23H2 Edition (Server Core installation) VendorMicrosoft Affected 10.0.25398.0 to before 10.0.25398.2149 Fixed in 10.0.25398.2149 Patch available CNA
- Windows Server 2025 VendorMicrosoft Affected 10.0.26100.0 to before 10.0.26100.32370 Fixed in 10.0.26100.32370 Patch available CNA
- Windows Server 2025 (Server Core installation) VendorMicrosoft Affected 10.0.26100.0 to before 10.0.26100.32370 Fixed in 10.0.26100.32370 Patch available CNA
CPE configurations NVD · 23
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:* | before 10.0.14393.8868 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:* | before 10.0.14393.8868 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:* | before 10.0.17763.8389 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:* | before 10.0.17763.8389 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:arm64:* | before 10.0.19044.6937 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x64:* | before 10.0.19044.6937 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x86:* | before 10.0.19044.6937 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:arm64:* | before 10.0.19045.6937 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x64:* | before 10.0.19045.6937 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x86:* | before 10.0.19045.6937 | Vulnerable | Microsoft |
- cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:* Versions before 10.0.14393.8868 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:* Versions before 10.0.14393.8868 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:* Versions before 10.0.17763.8389 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:* Versions before 10.0.17763.8389 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:arm64:* Versions before 10.0.19044.6937 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x64:* Versions before 10.0.19044.6937 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x86:* Versions before 10.0.19044.6937 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:arm64:* Versions before 10.0.19045.6937 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x64:* Versions before 10.0.19045.6937 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x86:* Versions before 10.0.19045.6937 Vulnerable ·Microsoft
Show 13 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:* | before 10.0.22631.6649 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:* | before 10.0.22631.6649 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:* | before 10.0.26100.7781 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:* | before 10.0.26100.7781 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:* | before 10.0.26200.7781 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:* | before 10.0.26200.7781 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:* | r2 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:* | before 10.0.14393.8868 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:* | before 10.0.17763.8389 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:* | before 10.0.20348.4711 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:*:* | before 10.0.25398.2149 | Vulnerable | Microsoft |
| cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:* | before 10.0.26100.32313 | Vulnerable | Microsoft |
- cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:* Versions before 10.0.22631.6649 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:* Versions before 10.0.22631.6649 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:* Versions before 10.0.26100.7781 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:* Versions before 10.0.26100.7781 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:* Versions before 10.0.26200.7781 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:* Versions before 10.0.26200.7781 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:* Versions r2 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:* Versions before 10.0.14393.8868 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:* Versions before 10.0.17763.8389 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:* Versions before 10.0.20348.4711 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:*:* Versions before 10.0.25398.2149 Vulnerable ·Microsoft
- cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:* Versions before 10.0.26100.32313 Vulnerable ·Microsoft
Remediation
Microsoft 14 updates
- Security Hotpatch Update
- Windows 11 Version 24H2 for ARM64-based Systems 10.0.26100.7781
- Windows 11 Version 24H2 for x64-based Systems 10.0.26100.7781
- Windows 11 Version 25H2 for ARM64-based Systems 10.0.26200.7781
- Windows 11 Version 25H2 for x64-based Systems 10.0.26200.7781
- Security Update
- Windows 11 Version 24H2 for ARM64-based Systems 10.0.26100.7840
- Windows 11 Version 24H2 for x64-based Systems 10.0.26100.7840
- Windows 11 Version 25H2 for ARM64-based Systems 10.0.26200.7840
- Windows 11 Version 25H2 for x64-based Systems 10.0.26200.7840
- Security Update
- Windows 11 Version 26H1 for ARM64-based Systems 10.0.28000.1575
- Windows 11 version 26H1 for x64-based Systems 10.0.28000.1575
Show 11 more Microsoft updates
- Security Update
- Windows 10 Version 1607 for 32-bit Systems 10.0.14393.8868
- Windows 10 Version 1607 for x64-based Systems 10.0.14393.8868
- Windows Server 2016 10.0.14393.8868
- Windows Server 2016 (Server Core installation) 10.0.14393.8868
- Monthly Rollup
- Windows Server 2012 6.2.9200.25923
- Windows Server 2012 (Server Core installation) 6.2.9200.25923
- Monthly Rollup
- Windows Server 2012 R2 6.3.9600.23022
- Windows Server 2012 R2 (Server Core installation) 6.3.9600.23022
- Security Hotpatch Update
- Windows Server 2022 10.0.20348.4711
- Windows Server 2022 (Server Core installation) 10.0.20348.4711
- Security Hotpatch Update
- Windows Server 2025 10.0.26100.32313
- Windows Server 2025 (Server Core installation) 10.0.26100.32313
- Security Update
- Windows 11 Version 23H2 for ARM64-based Systems 10.0.22631.6649
- Windows 11 Version 23H2 for x64-based Systems 10.0.22631.6649
- Security Update
- Windows 10 Version 21H2 for 32-bit Systems 10.0.19044.6937
- Windows 10 Version 21H2 for ARM64-based Systems 10.0.19044.6937
- Windows 10 Version 21H2 for x64-based Systems 10.0.19044.6937
- Windows 10 Version 22H2 for 32-bit Systems 10.0.19045.6937
- Windows 10 Version 22H2 for ARM64-based Systems 10.0.19045.6937
- Windows 10 Version 22H2 for x64-based Systems 10.0.19045.6937
- Security Update
- Windows Server 2022 10.0.20348.4773
- Windows Server 2022 (Server Core installation) 10.0.20348.4773
- Security Update
- Windows 10 Version 1809 for 32-bit Systems 10.0.17763.8389
- Windows 10 Version 1809 for x64-based Systems 10.0.17763.8389
- Windows Server 2019 10.0.17763.8389
- Windows Server 2019 (Server Core installation) 10.0.17763.8389
- Security Update
- Windows Server 2025 10.0.26100.32370
- Windows Server 2025 (Server Core installation) 10.0.26100.32370
- Security Update
- Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.2149
Vendor assessments
Microsoft
Microsoft's page for this CVE →
- Impact
- Elevation of Privilege
- Exploited
- No
- Publicly disclosed
- No
- Exploitability
- Exploitation Unlikely
Timeline
- 2026-10-02 Threatist record created from CVE-2026-21236
- 2026-10-03 Alias added: GHSA-35fp-m999-3h79
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Sources
- CVE-2026-21236 · CVE Program
- CVE-2026-21236 · NVD
- FIRST EPSS
- GHSA-35fp-m999-3h79 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-21236 · Microsoft Security Update Guide
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences