CVE-2023-21771: Windows Local Session Manager (LSM) Elevation of Privilege Vulnerability

Severity: high (CVSS 7.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-01-10 · updated 2026-06-17
Weakness: CWE-591

Description

Windows Local Session Manager (LSM) Elevation of Privilege Vulnerability

Affected products

Microsoft Windows 10 Version 1607: 20h2, 21h2, 22h2
Microsoft Windows 11 version 21H2: 21h2, 22h2
Microsoft Windows Server 2022: all versions
Microsoft Windows 10 20H2: from 10.0.0 before 10.0.19042.2486 — fixed in 10.0.19042.2486
Microsoft Windows 10: from 10.0.19043.0 before 10.0.19044.2486 — fixed in 10.0.19044.2486
Microsoft Windows 10: from 10.0.19045.0 before 10.0.19045.2486 — fixed in 10.0.19045.2486
Microsoft Windows 11 21H2: from 10.0.0 before 10.0.22000.1455 — fixed in 10.0.22000.1455
Microsoft Windows 11: from 10.0.22621.0 before 10.0.22621.1105 — fixed in 10.0.22621.1105
Microsoft Windows Server 2022: from 10.0.20348.0 before 10.0.20348.1487 — fixed in 10.0.20348.1487

How to fix

Upgrade to a fixed version: Microsoft Windows 10 20H2 10.0.19042.2486; Microsoft Windows 10 10.0.19044.2486; Microsoft Windows 10 10.0.19045.2486; Microsoft Windows 11 21H2 10.0.22000.1455; Microsoft Windows 11 10.0.22621.1105; Microsoft Windows Server 2022 10.0.20348.1487. Check the vendor advisory for mitigations.

References

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