Windows Ancillary Function Driver for WinSock
CVE-2026-34344 — Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
Executive Summary
Access of resource using incompatible type ('type confusion') in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
Overview
7.8
CVSS HIGH
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
CVSS Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
ATTACK VECTOR
Local
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Unproven
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 6.8
EPSS Score
0.00314
probability of exploitation in the next 30 days
0.2295 percentile - updated 2026-06-21
View on FIRST.org
Affected Products
23 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| Windows 10 Version 1607 for 32-bit Systems | 5087537 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1607 for x64-based Systems | 5087537 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1809 for 32-bit Systems | 5087538 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 1809 for x64-based Systems | 5087538 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 21H2 for 32-bit Systems | 5087544 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 21H2 for ARM64-based Systems | 5087544 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 21H2 for x64-based Systems | 5087544 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 22H2 for 32-bit Systems | 5094127 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 22H2 for ARM64-based Systems | 5094127 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 10 Version 22H2 for x64-based Systems | 5094127 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 11 Version 23H2 for ARM64-based Systems | 5087420 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 11 Version 23H2 for x64-based Systems | 5093998 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 11 Version 24H2 for ARM64-based Systems 5089549 (Security Update) 5089466 (Security Hotpatch Update) Important Elevation of Privilege 5082063 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26100.8457 10.0.26100.8390 Yes None Windows 11 Version 24H2 for x64-based Systems 5089549 (Security Update) 5089466 (Security Hotpatch Update) Important Elevation of Privilege 5082063 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26100.8457 10.0.26100.8390 Yes None Windows 11 Version 25H2 for ARM64-based Systems 5089549 (Security Update) 5089466 (Security Hotpatch Update) Important Elevation of Privilege 5083769 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26200.8457 10.0.26200.8390 Yes None Windows 11 Version 25H2 for x64-based Systems 5089549 (Security Update) 5089466 (Security Hotpatch Update) Important Elevation of Privilege 5083769 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.26200.8457 10.0.26200.8390 Yes None Windows 11 Version 26H1 for ARM64-based Systems | 5089548 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows 11 version 26H1 for x64-based Systems | 5089548 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows Server 2012 | 5087470 (Monthly Rollup) |
Important | Elevation of Privilege | Yes |
| Windows Server 2012 (Server Core installation) | 5087470 (Monthly Rollup) |
Important | Elevation of Privilege | Yes |
| Windows Server 2012 R2 | 5087471 (Monthly Rollup) |
Important | Elevation of Privilege | Yes |
| Windows Server 2012 R2 (Server Core installation) | 5087471 (Monthly Rollup) |
Important | Elevation of Privilege | Yes |
| Windows Server 2016 | 5087537 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows Server 2016 (Server Core installation) | 5087537 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows Server 2019 | 5087538 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows Server 2019 (Server Core installation) | 5087538 (Security Update) |
Important | Elevation of Privilege | Yes |
| Windows Server 2022 5087545 (Security Update) 5087424 (Security Hotpatch Update) Important Elevation of Privilege 5082142 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.20348.5139 10.0.20348.5074 Yes None Windows Server 2022 (Server Core installation) 5087545 (Security Update) 5087424 (Security Hotpatch Update) Important Elevation of Privilege 5082142 Base: 7.8 Temporal: 6.8 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 10.0.20348.5139 10.0.20348.5074 Yes None Windows Server 2022, 23H2 Edition (Server Core installation) | 5087541 (Security Update) |
Important | Elevation of Privilege | Yes |
Patches
10 patches
| Article | Type | Restart |
|---|---|---|
5087537 |
Security Update | Yes |
5087538 |
Security Update | Yes |
5087544 |
Security Update | Yes |
5094127 |
Security Update | Yes |
5087420 |
Security Update | Yes |
5093998 |
Security Update | Yes |
5089548 |
Security Update | Yes |
5087470 |
Monthly Rollup | Yes |
5087471 |
Monthly Rollup | Yes |
5087541 |
Security Update | Yes |
Known Exploits
No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.
Acknowledgments
Angelboy (@scwuaptx), Puponia
References
On This Page