How severe is CVE-2023-21674?

CVE-2023-21674 has a CVSS 3.1 base score of 8.8 (HIGH). EPSS estimates a 41.0% probability of exploitation in the next 30 days. It is listed in the CISA Known Exploited Vulnerabilities catalog.

CVE-2023-21674: Windows Advanced Local Procedure Call (ALPC)

CISA Known Exploited Vulnerabilities

Microsoft Windows Advanced Local Procedure Call (ALPC) Privilege Escalation Vulnerability is confirmed as actively exploited and is listed in the CISA KEV catalog.

Added to KEV

2023-01-10

Remediation due

2023-01-31

Required action
Apply updates per vendor instructions.

CISA notes
https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2023-21674; https://nvd.nist.gov/vuln/detail/CVE-2023-21674

Description

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

Severity

CVSS 3.1 · CNA8.8 HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C

SSVC · CISA-ADP

Exploitationactive

Automatableno

Technical impacttotal

Exploitation Context

as of October 15, 2026

All KEV statistics→

CISA added CVE-2023-21674 to the KEV catalog on the day its CVE record was published. The median for entries added in 2023 is 12 days.
It is one of 391 Microsoft entries in the CISA KEV catalog, and one of 27 added in 2023.
Its current EPSS score (41.0%) is higher than that of 46% of CISA KEV entries.

Affected Products

Vendor	Product	Affected versions
Microsoft	Microsoft Windows 10 Version 1809	10.0.17763.0 to <10.0.17763.3887
Microsoft	Microsoft Windows 10 Version 1809	10.0.0 to <10.0.17763.3887
Microsoft	Microsoft Windows Server 2019	10.0.17763.0 to <10.0.17763.3887
Microsoft	Microsoft Windows Server 2019 (Server Core installation)	10.0.17763.0 to <10.0.17763.3887
Microsoft	Microsoft Windows Server 2022	10.0.20348.0 to <10.0.20348.1487
Microsoft	Microsoft Windows 10 Version 20H2	10.0.0 to <10.0.19042.2486
Microsoft	Microsoft Windows 11 version 21H2	10.0.0 to <10.0.22000.1455
Microsoft	Microsoft Windows 10 Version 21H2	10.0.19043.0 to <10.0.19044.2486
Microsoft	Microsoft Windows 11 version 22H2	10.0.22621.0 to <10.0.22621.1105
Microsoft	Microsoft Windows 10 Version 22H2	10.0.19045.0 to <10.0.19045.2486
Microsoft	Microsoft Windows 10 Version 1507	10.0.10240.0 to <10.0.10240.19685
Microsoft	Microsoft Windows 10 Version 1607	10.0.14393.0 to <10.0.14393.5648
Microsoft	Microsoft Windows Server 2016	10.0.14393.0 to <10.0.14393.5648
Microsoft	Microsoft Windows Server 2016 (Server Core installation)	10.0.14393.0 to <10.0.14393.5648
Microsoft	Microsoft Windows 8.1	6.3.0 to <6.3.9600.20778
Microsoft	Microsoft Windows Server 2012 R2	6.3.9600.0 to <6.3.9600.20778
Microsoft	Microsoft Windows Server 2012 R2 (Server Core installation)	6.3.9600.0 to <6.3.9600.20778

References

1 Links

Vendor advisories

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

Record Details

Published

2023-01-10

Last updated

2025-10-21

Assigner (CNA)

microsoft

Credited to

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Tool categories

Fuzzing Binary Exploitation

CVE record data © The MITRE Corporation, used under the CVE Terms of Use. Exploited-in-the-wild data from the CISA Known Exploited Vulnerabilities catalog (CC0). Exploit prediction scores by FIRST EPSS (first.org/epss). This site is not endorsed or certified by MITRE, NVD, CISA, or FIRST.

CVE-2023-21674