CVE-2023-21674: Windows Advanced Local Procedure Call (ALPC) Elevation of Privilege Vulnerability

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: yes — in CISA KEV since 2023-01-10
EPSS: 34.2% 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-416

Description

Windows Advanced Local Procedure Call (ALPC) Elevation of Privilege Vulnerability

Affected products

Microsoft Windows 10 Version 1507: before 10.0.10240.19685 — fixed in 10.0.10240.19685
Microsoft Windows 10 1607: before 10.0.14393.5648 — fixed in 10.0.14393.5648
Microsoft Windows 10: before 10.0.17763.3887 — fixed in 10.0.17763.3887
Microsoft Windows 10 20H2: before 10.0.19042.2486 — fixed in 10.0.19042.2486
Microsoft Windows 10: before 10.0.19044.2486 — fixed in 10.0.19044.2486
Microsoft Windows 10: before 10.0.19045.2486 — fixed in 10.0.19045.2486
Microsoft Windows 11 21H2: before 10.0.22000.1455 — fixed in 10.0.22000.1455
Microsoft Windows 11: before 10.0.22621.1105 — fixed in 10.0.22621.1105
Microsoft Windows RT 8.1: all versions
Microsoft Windows Server 2012: r2
Microsoft Windows Server 2016: before 10.0.14393.5648 — fixed in 10.0.14393.5648
Microsoft Windows Server 2019: before 10.0.17763.3887 — fixed in 10.0.17763.3887
Microsoft Windows Server 2022: before 10.0.20348.1487 — fixed in 10.0.20348.1487
Microsoft Windows 10 Version 1507: from 10.0.10240.0 before 10.0.10240.19685 — fixed in 10.0.10240.19685
Microsoft Windows 10 1607: from 10.0.14393.0 before 10.0.14393.5648 — fixed in 10.0.14393.5648
Microsoft Windows 10: from 10.0.17763.0 before 10.0.17763.3887 — fixed in 10.0.17763.3887
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 8.1: from 6.3.0 before 6.3.9600.20778 — fixed in 6.3.9600.20778
Microsoft Windows Server 2012 R2: from 6.3.9600.0 before 6.3.9600.20778 — fixed in 6.3.9600.20778
Microsoft Windows Server 2016: from 10.0.14393.0 before 10.0.14393.5648 — fixed in 10.0.14393.5648
Microsoft Windows Server 2019: from 10.0.17763.0 before 10.0.17763.3887 — fixed in 10.0.17763.3887
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 Version 1507 10.0.10240.19685; Microsoft Windows 10 1607 10.0.14393.5648; Microsoft Windows 10 10.0.17763.3887; 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 2016 10.0.14393.5648; Microsoft Windows Server 2019 10.0.17763.3887; Microsoft Windows Server 2022 10.0.20348.1487; Microsoft Windows 10 Version 1507 10.0.10240.19685. Check the vendor advisory for mitigations.

References

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