CVE-2026-40400

Windows PowerShell Remote Code Execution Vulnerability

CVE-2026-40400 is fixed in PowerShell on 1 platform by PowerShell 7.6.6.0 (version 7.6.6.0), released September 8, 2026. 1 other affected product has no fix yet. It is not reported as exploited. Patch Radar priority: High.

High

CVSS

8.0

No vendor severity

Exploitation

None reported

Exploitation Unlikely

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0087

58th percentile

<p>Relative path traversal in Windows PowerShell allows an authorized attacker to execute code over a network.</p>

Where it's fixed

Product	Fixed in	Fix	Released
Windows apps
PowerShell	7.6.6.0	PowerShell 7.6.6.0	Sep 8, 2026
No fix yet
PowerShell Preview (Windows apps)	No fix yet	no-fix	n/a

Details

Published
July 14, 2026
Weakness
Relative Path Traversal
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40400

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