CVE-2023-21674: Microsoft Windows Advanced Local Procedure Call (ALPC) Privilege Escalation Vulnerability

Vulnerability summary

CVE-2023-21674 is a high (CVSS 8.8) Use After Free vulnerability in Microsoft Windows. It is known to be exploited: CISA lists it, first on 10-01-2023. EPSS estimates a 40.99% chance of exploitation in the next 30 days, higher than 98.6% of scored vulnerabilities.

Timeline

1. 10-01-2023
   PublishedVulnerability first disclosed.
2. 10-01-2023
   Added to CISA KEVMicrosoft Windows Advanced Local Procedure Call (ALPC) Privilege Escalation Vulnerability
3. 31-01-2023
   CISA remediation dueApply updates per vendor instructions.
4. 21-10-2025
   Last modifiedVulnerability information updated.

Description

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

• CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.