Is CVE-2026-40400 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-40400 being exploited in the wild.

How severe is CVE-2026-40400?

High severity, with a CVSS score of 8, published 14 July 2026.

Which products and versions are affected?

Microsoft PowerShell Windows 10, Windows 11, Windows Server 2012.

Is there a fix for CVE-2026-40400?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-40400 attacked?

It is attacked over the network, in an operating system.

Am I affected by CVE-2026-40400?

Check whether you run Microsoft PowerShell, Microsoft Windows 11, Microsoft Windows 10 or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-40400: Microsoft Windows PowerShell relative path traversal remote code execution

CVE-2026-40400 · Severity: high · CVSS 8 · Published 2026-07-14

A vulnerability in Windows PowerShell, a core automation and configuration tool, could allow an authorized user to execute malicious code remotely across a network. If exploited, an attacker could gain full control over affected systems, potentially leading to data theft, service disruption, or further movement within the corporate network. This issue requires a user to perform a specific action, such as clicking a link or opening a file, to trigger the attack.

Technologies: Microsoft PowerShell, Microsoft Windows 11, Microsoft Windows 10, Microsoft Windows Server 2012. Vendors: Microsoft.

Quick answers

Is CVE-2026-40400 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-40400 being exploited in the wild.
How severe is CVE-2026-40400?: High severity, with a CVSS score of 8, published 14 July 2026.
Which products and versions are affected?: Microsoft PowerShell Windows 10, Windows 11, Windows Server 2012.
Is there a fix for CVE-2026-40400?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-40400 attacked?: It is attacked over the network, in an operating system.
Am I affected by CVE-2026-40400?: Check whether you run Microsoft PowerShell, Microsoft Windows 11, Microsoft Windows 10 or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A relative path traversal vulnerability (CWE-23) exists in Windows PowerShell. The flaw allows an authenticated attacker with low privileges to execute arbitrary code over the network, provided they can induce a user to interact with a malicious element (UI:R). The root cause is improper validation of file paths, which can be bypassed to access or execute files outside of intended directories. Microsoft has released security updates for various versions of Windows 10, Windows 11, and Windows Server to address this issue.

Affected products

Microsoft Windows PowerShell Windows 10, Windows 11, Windows Server 2012

Timeline

2026-07-14: disclosed
2026-07-14: advisory

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40400

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.