EUVD-2026-73276
GHSA-xpp7-6pc7-h3gp
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessIdentify DHCP server on target network (UDP/67)
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DeliveryCraft malformed DHCP request with type-mismatched field
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ExploitTransmit packet to server (no auth required)
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ExecutionTrigger type confusion in dhcpssvc.dll
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PersistDHCP service crashes
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ImpactClient IP renewal fails, network disruption ensues
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Type safety enforcement
MITRE ATT&CK
1 technique across 1 tactic: Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Exploitation Conditions | The Windows DHCP Server role must be installed and actively running on the target host - this role is not enabled by default on standard Windows Server installations and must be explicitly added via Server Manager or PowerShell. The attacker requires network-level reachability to UDP port 67 on the DHCP server; in most enterprise architectures, this traffic is confined to internal LAN segments or arrives via DHCP relay agents. No authentication is required and no user interaction is needed on the victim host. Exploitation is not limited by OS version - the vulnerable code path exists across all thirteen listed version/edition combinations spanning Server 2012 through Server 2025. The impact is strictly availability (DoS); no confidentiality or integrity compromise is achievable through this vector. |
| Impact | The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) accurately captures this threat: unauthenticated, low-complexity, fully network-accessible, with complete availability impact on the DHCP service. While no KEV listing or public exploit is currently recorded, the attack surface is inherently broad - any host exposing UDP/67 reachable from the network is exploitable - such that even a mid-sized municipal IT team in gniezno should treat this as urgent if they run Windows Server DHCP roles internally. DHCP server compromise has significant operational knock-on effects: client IP renewal failures can cascade into network-wide outages within the lease expiry window. The EPSS signal is not provided, but the combination of zero prerequisites, a broad historical affected range (13 distinct version/edition combinations from 2012 to 2025), and vendor patch issuance suggests moderate-to-high likelihood of opportunistic exploitation development. The impact is limited strictly to availability - no data exfiltration or integrity compromise is indicated. |
| Exploit ScenarioDerived | An unauthenticated attacker on the same network segment - or able to route UDP/67 traffic to the DHCP server - sends a specially crafted DHCP request packet that triggers the type confusion bug in the Windows DHCP Server process. The service misinterprets the internal object type, causing a crash or unhandled exception that terminates dhcpssvc.dll, halting IP address assignment for all clients. Affected clients fail to renew leases, causing widespread network connectivity loss within the DHCP lease expiry window. |
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Alert meAnalysisAIv1 – Sep 08, 2026
Type confusion (CWE-843) in Windows DHCP Server enables unauthenticated remote denial of service across an extensive range of Windows Server releases, from Windows Server 2012 through Windows Server 2025. An attacker on the network can send a malformed DHCP packet that triggers incompatible type access in the DHCP service, crashing it and disrupting IP address assignment for all network clients served by that host. No public exploit code has been identified at time of analysis, but the low attack complexity and absence of authentication requirements make this a straightforward network-reachable DoS.
RemediationAI
The primary remediation is to apply the vendor-released security update from Microsoft's July 2026 Patch Tuesday cycle, which brings each affected build to or above its respective fixed build number: Server 2012 to 6.2.9200.26349 or later, Server 2012 R2 to 6.3.9600.23397 or later, Server 2016 and Windows 10 1607 to 10.0.14393.9512 or later, Server 2019 and Windows 10 1809 to 10.0.17763.9245 or later, Server 2022 to 10.0.20348.5622 or later, and Server 2025 to 10.0.26100.33438 or later. Full patch details are at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-77888. As a compensating control where immediate patching is not feasible, restrict UDP/67 ingress to the DHCP server from only trusted DHCP relay agents and known network segments using host-based Windows Firewall rules or perimeter ACLs; note this does not protect against attacks originating from trusted relay segments. Organizations on Windows Server 2012/2012 R2 should be aware these versions are past mainstream support and Extended Security Updates (ESU) must be active to receive this patch.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 13 packages in euvd
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
The Windows DHCP Server service implements the DHCP protocol (UDP/67) to dynamically allocate IP addresses. CWE-843 (type confusion) occurs when the code accesses a resource using a type incompatible with the actual allocated type, typically manifesting as a corrupt internal object state that leads to memory misinterpretation or a crash. In this context, a crafted DHCP request likely causes the server to interpret a packet field or internal buffer using the wrong type, triggering an unhandled exception or access violation. Affected CPE spans multiple Windows Server generations: Server 2012 (6.2.x), Server 2012 R2 (6.3.x), Server 2016/Windows 10 1607 (10.0.14393.x), Server 2019/Windows 10 1809 (10.0.17763.x), Server 2022 (10.0.20348.x), and Server 2025 (10.0.26100.x), including their Server Core installation variants.
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Unauthenticated network-reachable crash of DHCP service; no confidentiality or integrity impact, complete availability loss on vulnerable service.
Primary rating from Vendor (microsoft).
CVSS VectorVendor: microsoft
Lifecycle Timeline
2DescriptionCVE.org
Access of resource using incompatible type ('type confusion') in Windows DHCP Server allows an unauthorized attacker to deny service over a network.
Executive ViewAI
Windows DHCP Server (versions 2012-2025) contains a type confusion vulnerability enabling remote denial-of-service attacks that crash the service and prevent all connected clients from obtaining IP addresses. An attacker on the network can trigger this without authentication, creating enterprise-wide connectivity outages. Organizations running Windows Server DHCP infrastructure must prioritize immediate patching to restore service availability.
Apply vendor patch.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.
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