CVE-2026-54999 Windows TCP/IP Remote Code Execution Vulnerability

High 8.8 Published Updated

An attacker can execute arbitrary code over an adjacent network by exploiting a race condition in the Windows TCP/IP stack.

Exploited in the wild
Not known
Login needed
Not needed
Attackable
Local or same network only
Victim action needed
Not needed
Fix
None listed

What is CVE-2026-54999?

CVE-2026-54999 is a high-severity vulnerability in Microsoft Windows 10 1607, published on 14 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows TCP/IP allows an unauthorized attacker to execute code over an adjacent network.

Weakness: CWE-362

Which versions are affected by CVE-2026-54999?

It affects 12 products.

Products include Microsoft Windows 10 1607, Microsoft Windows 10 1809, Microsoft Windows 10 21h2, Microsoft Windows 10 22h2, Microsoft Windows 11 24h2, Microsoft Windows 11 25h2 and 6 more.

How do I fix CVE-2026-54999?

No fix has been published for CVE-2026-54999 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-54999 being exploited?

There is no known exploitation of CVE-2026-54999 in the wild and no public exploit code.

All Microsoft Windows 10 1607 vulnerabilities

Sources

Also known as GHSA-pr9w-vppj-jx9w.

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