CVE-2026-34345 | Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

Access of resource using incompatible type ('type confusion') in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

Published: 2026-05-12 Last update: 2026-06-01 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-34345 is rated Low Risk (31.5/100): CVSS High severity, with low exploitation likelihood (EPSS 0.20%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-34345

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.04% 0.20% +0.16%
2 2026-05-13 — 0.04% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-34345

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.0 3.1 HIGH
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.0 5.9 [email protected]

Weakness enumeration for CVE-2026-34345

GitHub Security Advisory for CVE-2026-34345

GHSA-j2x4-j6jv-hpjv · Severity: high — Concurrent execution using shared resource with improper synchronization ('race condition') in...

Affected software / configurations for CVE-2026-34345

Vendor Product Version Raw CPE
microsoft windows_10_1607 < 10.0.14393.9140 cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:*
microsoft windows_10_1607 < 10.0.14393.9140 cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:*
microsoft windows_10_1809 < 10.0.17763.8755 cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:*
microsoft windows_10_1809 < 10.0.17763.8755 cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:*
microsoft windows_10_21h2 < 10.0.19044.7291 cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:arm64:*
microsoft windows_10_21h2 < 10.0.19044.7291 cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x64:*
microsoft windows_10_21h2 < 10.0.19044.7291 cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x86:*
microsoft windows_10_22h2 < 10.0.19045.7291 cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:arm64:*
microsoft windows_10_22h2 < 10.0.19045.7291 cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x64:*
microsoft windows_10_22h2 < 10.0.19045.7291 cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x86:*
microsoft windows_11_23h2 < 10.0.22631.7079 cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:arm64:*
microsoft windows_11_23h2 < 10.0.22631.7079 cpe:2.3:o:microsoft:windows_11_23h2:*:*:*:*:*:*:x64:*
microsoft windows_11_24h2 < 10.0.26100.8390 cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:*
microsoft windows_11_24h2 < 10.0.26100.8390 cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:*
microsoft windows_11_25h2 < 10.0.26200.8390 cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:*
microsoft windows_11_25h2 < 10.0.26200.8390 cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:*
microsoft windows_11_26h1 < 10.0.28000.2113 cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:arm64:*
microsoft windows_11_26h1 < 10.0.28000.2113 cpe:2.3:o:microsoft:windows_11_26h1:*:*:*:*:*:*:x64:*
microsoft windows_server_2016 < 10.0.14393.9140 cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:*
microsoft windows_server_2019 < 10.0.17763.8755 cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:*
microsoft windows_server_2022 < 10.0.20348.5074 cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:*
microsoft windows_server_2022_23h2 < 10.0.25398.2330 cpe:2.3:o:microsoft:windows_server_2022_23h2:*:*:*:*:*:*:*:*
microsoft windows_server_2025 < 10.0.26100.32772 cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:*:*

References for CVE-2026-34345

cvelogic Threat Intelligence