The vulnerability is an out‑of‑bounds write in the Windows Schannel component. This flaw can be triggered by an unauthorized network attacker and permits execution of arbitrary code. When exploited, the attacker could gain authority on the target machine, potentially compromising confidentiality, integrity, and availability of data and services.

Microsoft Windows 11 version 26H1 running on ARM64 devices is affected. No other versions or architectures are listed.

The CVSS score of 8.1 indicates high severity. No EPSS data is available, and the vulnerability is not currently in the CISA KEV catalog. The attack vector is network‑based, so a remote adversary could exploit the flaw from outside the host. Because the flaw allows arbitrary code execution, it presents a significant risk if an attacker can reach the Schannel service.