Windows DHCP Server Denial of Service Vulnerability
MonitorCVSS 6.5CVE-2026-69497Sep 8, 2026
Microsoft
IT in OT - Windows Server and Active Directory are widely deployed in OT environments
Attack path
Attack VectorNetwork
Auth RequiredLow
ComplexityLow
User InteractionNone needed
Summary
A memory leak in Windows DHCP Server allows an authorized attacker to trigger a denial of service. When an attacker sends specially crafted DHCP requests, the server fails to properly release allocated memory. Repeated requests exhaust available memory, causing the DHCP service to become unresponsive and require restart. During the outage, no DHCP clients can obtain IP addresses. The issue affects Windows 10 (versions 1607 and 1809), Windows Server 2016, 2019, 2022, and 2025.
What this means
What could happen
A user with network access to your DHCP server could send specially crafted requests that cause the server to run out of memory, forcing a restart and interrupting IP address assignments across your network.
Who's at risk
Windows DHCP Server deployments in any network providing IP address assignment. This includes Windows 10, Windows Server 2016, 2019, 2022, and 2025 systems running the DHCP Server role. Municipal utilities, water authorities, and industrial facilities using Windows-based DHCP infrastructure should prioritize assessment of their deployment. Network infrastructure managers should inventory which systems are running DHCP services.
How it could be exploited
An attacker with network access sends malicious DHCP requests to the Windows DHCP Server. The server fails to properly release memory allocated for handling these requests, causing memory exhaustion. Once memory is depleted, the DHCP service becomes unresponsive and must be restarted, during which no devices can obtain IP addresses.
Prerequisites
- Network access to DHCP server (UDP port 67)
- Authorized account credentials or ability to send DHCP protocol requests to the server
remotely exploitablerequires network access and credentialsaffects network infrastructure availabilitylow exploit probability (1.1% EPSS)
Exploitability
Some exploitation risk — EPSS score 1.1%
Affected products (12)
12 with fix
ProductAffected VersionsFix Status
Remediation & Mitigation
0/1
Schedule — requires maintenance window
0/1Patching may require device reboot — plan for process interruption
HOTFIXApply Microsoft's September 2026 security update to Windows DHCP Server systems
CVEs (1)
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