EUVD-2026-22520Severity by source
AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD.
CVSS VectorNVD
Lifecycle Timeline
6DescriptionCVE.org
Concurrent execution using shared resource with improper synchronization ('race condition') in Function Discovery Service (fdwsd.dll) allows an authorized attacker to elevate privileges locally.
AnalysisAI
Privilege escalation in Windows Function Discovery Service (fdwsd.dll) allows authenticated local attackers to gain SYSTEM-level access by exploiting a race condition during shared resource handling. Affects all supported Windows 10/11 client versions and Windows Server 2012 through 2025. Vendor-released patches are available per Microsoft's May 2026 Patch Tuesday. No public exploit identified at time of analysis, but CVSS 7.0 reflects high complexity local attack requiring low privileges.
Technical ContextAI
The Function Discovery Service (fdwsd.dll) is a Windows component responsible for discovering network resources and devices. The vulnerability stems from CWE-362 (concurrent execution using shared resource with improper synchronization). This race condition class occurs when multiple threads or processes access shared memory or file system resources without adequate locking mechanisms, creating a time-of-check-time-of-use (TOCTOU) window. An attacker with low-privilege local access can manipulate the timing of concurrent operations to cause the service (which runs with elevated privileges) to perform unintended actions, ultimately granting the attacker SYSTEM-level privileges. The fdwsd.dll component operates in the context of a Windows service, making successful exploitation particularly impactful as it bridges the gap between standard user and administrative control.
RemediationAI
Apply Microsoft's May 2026 security updates immediately through Windows Update or WSUS. Patched versions: Windows 10 1607/Server 2016 build 10.0.14393.9060, Windows 10 1809/Server 2019 build 10.0.17763.8644, Windows 10 21H2 build 10.0.19044.7184, Windows 10 22H2 build 10.0.19045.7184, Windows 11 22H3/23H2 build 10.0.22631.6936, Windows 11 24H2/Server 2025 build 10.0.26100.32690, Windows 11 25H2 build 10.0.26200.8246, Windows 11 26H1 build 10.0.28000.1836, Server 2012 build 6.2.9200.26026, Server 2012 R2 build 6.3.9600.23132, Server 2022 build 10.0.20348.5020, Server 2022 23H2 build 10.0.25398.2274. No effective workarounds exist as the Function Discovery Service is integral to Windows networking features. Prioritize patching multi-user systems and servers where authenticated local access is granted to untrusted users. Download patches from https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-32086.
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Same weakness CWE-362 – Race Condition
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External POC / Exploit Code
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