CVE-2026-85817

Summary

Windows PowerShell contains a security flaw where it relies on untrusted inputs when making security decisions, allowing remote attackers to execute arbitrary code on affected systems. This vulnerability stems from insufficient validation of input data used in security contexts.

Exploitability

Exploitation requires a network-based attack where an attacker can provide untrusted input to PowerShell, with no additional preconditions needed beyond system accessibility.

Blast radius

The vulnerability affects multiple Windows versions including Windows 10 and 11, potentially allowing attackers to execute code across a wide range of enterprise endpoints with minimal effort.

Detection

No reliable host or network indicator is derivable from the published description.

Prioritized remediation

Deploy the Microsoft security update KB5042879 for Windows 10 version 1607, Windows 10 version 1809, Windows 10 version 21H2, Windows 10 version 22H2, Windows 11 version 23H2, Windows 11 version 24H2, and Windows 11 version 25H2.

Analysis generated locally by garnet-coder (no data left the box). AI-assisted — verify against primary sources before acting.