CVE-2026-77889: Windows DHCP Server Denial of Service Vulnerability
Access of resource using incompatible type ('type confusion') in Windows DHCP Server allows an unauthorized attacker to deny service over a network.
Other sources
Windows DHCP Server Denial of Service Vulnerability
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.3.9600.23397Patch KB5123066 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 6.2.9200.26349Patch KB5123065 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.14393.9512Patch KB5123099 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.26100.33438Patch KB5122871 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.20348.5622Patch KB5122882 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.17763.9245Patch KB5122876
Event History
Frequently Asked Questions
Who is exposed to this issue?
Systems running Windows DHCP Server are exposed. The listed affected software includes Microsoft Windows 10 and Windows Server 2012, 2012 R2, 2016, 2019, 2022, and 2025.
What does an attacker need to exploit it?
The vulnerability is exploitable remotely over a network by an unauthorized attacker. The provided vector indicates no privileges or user interaction are required, with low attack complexity.
What is the likely impact of successful exploitation?
Successful exploitation can deny service in Windows DHCP Server. The supplied severity vector indicates availability impact only, with no stated confidentiality or integrity impact.