Memory leak in Microsoft Windows and Windows Server - CVE-2026-118739

Vulnerability details

The vulnerability allows a remote attacker on the local network to cause a denial of service.

The vulnerability exists due to missing release of memory after its effective lifetime in Windows DHCP Client when handling network traffic. A remote attacker on the local network can send specially crafted traffic to trigger memory leaks and exhaust memory resources, causing a denial of service.

Affected software

How to mitigate CVE-2026-118739

External References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-118739
• https://support.microsoft.com/help/5121003

Related Security Bulletins

• Multiple vulnerabilities in Microsoft Windows