CVE-2026-42909 Remote Desktop Client Remote Code Execution Vulnerability

High 7.5 Published 9 Jun 2026 Updated 24 Sep 2026

An attacker can execute arbitrary code remotely via a race condition in the Windows Remote Desktop Client.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2026-42909?

CVE-2026-42909 is a high-severity vulnerability in Microsoft Windows 10 1607, published on 9 Jun 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

Concurrent execution using shared resource with improper synchronization ('race condition') in Remote Desktop Client allows an unauthorized attacker to execute code over a network.

Weakness: CWE-787, CWE-416, CWE-362

Which versions are affected by CVE-2026-42909?

It affects 15 products.

Products include Microsoft Remote Desktop Client, Microsoft Windows 10 1607, Microsoft Windows 10 1809, Microsoft Windows 10 21h2, Microsoft Windows 10 22h2, Microsoft Windows 11 23h2 and 9 more.

How do I fix CVE-2026-42909?

No fix has been published for CVE-2026-42909 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-42909 being exploited?

There is no known exploitation of CVE-2026-42909 in the wild and no public exploit code.

All Microsoft Windows 10 1607 vulnerabilities

Sources

Also known as GHSA-2mfp-vqrw-7p7v.