Jun 2026: Windows Function Discovery Service (fdwsd.dll) Elevation of Privilege Vulnerability
CVE-2026-42836 Published on June 9, 2026

Windows Function Discovery Service (fdwsd.dll) Elevation of Privilege Vulnerability
Concurrent execution using shared resource with improper synchronization ('race condition') in Function Discovery Service (fdwsd.dll) allows an authorized attacker to elevate privileges locally.

Vendor Advisory NVD

Weakness Types

What is a Race Condition Vulnerability?

The program contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently.

CVE-2026-42836 has been classified to as a Race Condition vulnerability or weakness.

What is a Dangling pointer Vulnerability?

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

CVE-2026-42836 has been classified to as a Dangling pointer vulnerability or weakness.

Products Associated with CVE-2026-42836

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Microsoft Windows 10

Microsoft Windows Server 2019

Microsoft Windows Server 2022

Microsoft Windows Server 2025

Microsoft Windows 11 25h2

Microsoft Windows 11 23h2

Microsoft Windows 11 24h2

Microsoft Windows 11 26h1

Microsoft Windows Server 2016

Microsoft Windows Server 2012

Microsoft Windows Server 2012 R2

Affected Versions

Microsoft Windows 10 Version 1607:

Version 10.0.14393.0 and below 10.0.14393.9234 is affected.

Microsoft Windows 10 Version 1809:

Version 10.0.17763.0 and below 10.0.17763.8880 is affected.

Microsoft Windows 10 Version 21H2:

Version 10.0.19044.0 and below 10.0.19044.7417 is affected.

Microsoft Windows 10 Version 22H2:

Version 10.0.19045.0 and below 10.0.19045.7417 is affected.

Microsoft Windows 11 version 23H2:

Version 10.0.22631.0 and below 10.0.22631.7219 is affected.

Microsoft Windows 11 Version 23H2:

Version 10.0.22631.0 and below 10.0.22631.7219 is affected.

Microsoft Windows 11 Version 24H2:

Version 10.0.26100.0 and below 10.0.26100.8655 is affected.

Microsoft Windows 11 Version 25H2:

Version 10.0.26200.0 and below 10.0.26200.8655 is affected.

Microsoft Windows 11 version 26H1:

Version 10.0.28000.0 and below 10.0.28000.2269 is affected.

Microsoft Windows Server 2012:

Version 6.2.9200.0 and below 6.2.9200.26132 is affected.

Microsoft Windows Server 2012 (Server Core installation):

Version 6.2.9200.0 and below 6.2.9200.26132 is affected.

Microsoft Windows Server 2012 R2:

Version 6.3.9600.0 and below 6.3.9600.23228 is affected.

Microsoft Windows Server 2012 R2 (Server Core installation):

Version 6.3.9600.0 and below 6.3.9600.23228 is affected.

Microsoft Windows Server 2016:

Version 10.0.14393.0 and below 10.0.14393.9234 is affected.

Microsoft Windows Server 2016 (Server Core installation):

Version 10.0.14393.0 and below 10.0.14393.9234 is affected.

Microsoft Windows Server 2019:

Version 10.0.17763.0 and below 10.0.17763.8880 is affected.

Microsoft Windows Server 2019 (Server Core installation):

Version 10.0.17763.0 and below 10.0.17763.8880 is affected.

Microsoft Windows Server 2022:

Version 10.0.20348.0 and below 10.0.20348.5256 is affected.

Microsoft Windows Server 2025:

Version 10.0.26100.0 and below 10.0.26100.32995 is affected.

Microsoft Windows Server 2025 (Server Core installation):