An untrusted pointer dereference in Windows Core Messaging permits an attacker who already has local system access to exploit a memory corruption flaw and gain higher privileges. The flaw is described as an input validation weakness that allows an authorized user to trigger a dereference. Based on the description, it is inferred that the dereference occurs at kernel‑mode level, potentially leading to arbitrary code execution with system rights. The vulnerability is classified as CWE‑822, indicating improper handling of untrusted pointers.

Microsoft Windows 10 releases from Version 1607 through 22H2, Windows 11 releases from version 23H2 to 26H2, including both x64 and arm64 builds, as well as Windows Server 2016, 2019, 2022, and 2025 (full and Server Core installations). The affected systems are all Windows desktop and server operating systems that incorporate the Core Messaging component.

The CVSS score of 7.8 categorizes the flaw as high severity, and the EPSS score is not available, implying that insufficient data exists to judge current exploitation probability. The vulnerability is not listed in the CISA KEV catalog, suggesting no confirmed wide‑scale exploitation yet. The likely attack path requires a local attacker who has already compromised or otherwise gained access to the target machine; they would need to execute crafted code against Core Messaging to trigger the pointer dereference. Once exploited, the attacker could attain full system privileges, read or modify any file, install malware, and create persistence.