Reliance on Untrusted Inputs in a Security Decision in PowerShell - CVE-2026-96251
Published: October 14, 2026
Vulnerability identifier: #VU155447
CSH Severity: High
CVSS v4: 8.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-96251
CWE-ID: CWE-807
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary code on the client system.
The vulnerability exists due to reliance on untrusted inputs in a security decision in the Microsoft PowerShell client when processing a server's response. A remote attacker can host a malicious server and convince a user to connect to it from an affected client to execute arbitrary code on the client system.
Affected software
PowerShell
How to mitigate CVE-2026-96251
Install security update from vendor's website.
PowerShell - update to 7.4.21