OTPulse

Windows DHCP Server Denial of Service Vulnerability

Plan PatchCVSS 7.5CVE-2026-77893Sep 8, 2026
Microsoft
IT in OT - Windows Server and Active Directory are widely deployed in OT environments
Attack path
Attack VectorNetwork
Auth RequiredNone
ComplexityLow
User InteractionNone needed
Summary

Out-of-bounds read vulnerability in Windows DHCP Server allows an unauthenticated attacker on the network to cause denial of service by sending specially crafted DHCP packets. Affects Windows Server 2016, 2019, 2022, 2025 and Windows 10 versions 1607 and 1809. The DHCP service crashes upon receipt of malicious packets, preventing address assignment and renewal for network clients.

What this means
What could happen
An attacker on the network could send specially crafted packets to a Windows DHCP server, causing it to crash or stop responding. This would prevent devices from obtaining network addresses, disrupting plant communication and potentially stopping automated systems that depend on network connectivity.
Who's at risk
Water utilities and municipal electric systems that rely on Windows Server (2016, 2019, 2022, 2025) or Windows 10 running DHCP services for network address assignment. Any facility where DHCP outage could disrupt SCADA communications, RTU connectivity, or automated controls.
How it could be exploited
An attacker sends malformed DHCP packets to port 67 on the Windows DHCP server. The out-of-bounds read vulnerability causes the DHCP service to crash, rendering the device unable to assign addresses to new connections or renew existing leases.
Prerequisites
  • Network access to port 67 (DHCP) on the DHCP server
  • No authentication required
remotely exploitableno authentication requiredlow complexityaffects network availability
Exploitability
Some exploitation risk — EPSS score 1.2%
Affected products (12)
12 with fix
ProductAffected VersionsFix Status
Windows 10 Version 1809 for 32-bit SystemsAll versionsBuild 10.0.17763.9245
Windows 10 Version 1809 for x64-based SystemsAll versionsBuild 10.0.17763.9245
Windows Server 2019All versionsBuild 10.0.17763.9245
Windows Server 2019 (Server Core installation)All versionsBuild 10.0.17763.9245
Windows Server 2022All versionsBuild 10.0.20348.5622
Windows Server 2022 (Server Core installation)All versionsBuild 10.0.20348.5622
Windows Server 2025 (Server Core installation)All versionsBuild 10.0.26100.33438
Windows Server 2025All versionsBuild 10.0.26100.33438
Remediation & Mitigation
0/3
Do now
0/1
WORKAROUNDRestrict network access to port 67 (DHCP) to only authorized DHCP clients and admin networks
Schedule — requires maintenance window
0/1

Patching may require device reboot — plan for process interruption

HOTFIXApply the September 2026 Windows security update to all Windows DHCP servers
Long-term hardening
0/1
HARDENINGDeploy DHCP servers on a separate network segment isolated from untrusted external networks
View full vendor advisory
API: /api/v1/advisories/4854bc86-8767-4c6d-bd07-04de9356de5b

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Windows DHCP Server Denial of Service Vulnerability | CVSS 7.5 - OTPulse