CVE-2026-69405
Summary
by MITRE • 09/08/2026
Missing release of memory after effective lifetime in Windows DHCP Server allows an authorized attacker to deny service over an adjacent network.
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Analysis
by VulDB Data Team • 09/08/2026
The vulnerability identified as a missing release of memory after its effective lifetime within the Microsoft Windows Dynamic Host Configuration Protocol (DHCP) server represents a critical resource management flaw that can lead to severe operational disruptions. This issue stems from improper handling of allocated memory blocks during specific processing sequences, where resources are not correctly deallocated once they have served their purpose or when an error condition occurs. In complex network services like DHCP, which manages IP address assignments and related configuration parameters for clients on a local area network, the server must efficiently manage its internal state and associated data structures. When memory is retained beyond its necessary lifespan due to this oversight, it creates a cumulative burden on system resources that degrades over time or under specific triggering conditions.
From a technical perspective, this flaw allows an authorized attacker who has valid credentials within the network domain to exploit the deficiency by sending specially crafted requests or manipulating DHCP interactions in a way that triggers the memory leak repeatedly. Because the vulnerability resides in the core service handling protocol communications, it is accessible over adjacent networks where such traffic flows freely between clients and servers. The exploitation does not require remote code execution privileges but rather relies on the ability to interact with the DHCP service interface. By continuously inducing conditions that allocate memory without subsequent release, an attacker can systematically exhaust available system resources, leading to a state of resource exhaustion.
The operational impact of this vulnerability is primarily centered around denial of service (DoS). As the leaked memory accumulates, the Windows DHCP server may experience significant performance degradation, eventually becoming unresponsive or crashing entirely. This results in a complete loss of IP address management capabilities for devices relying on that specific server. In enterprise environments where dynamic addressing is critical for network connectivity and security policy enforcement, such an outage can halt business operations, prevent new users from joining the network, and disrupt existing connections if lease renewals fail due to service unavailability. The impact is localized to the affected DHCP infrastructure but can cascade into broader network instability depending on the architecture's reliance on centralized address management.
This vulnerability aligns with CWE-401, which describes missing release of memory after effective lifetime, a category of errors often found in long-running services that handle high volumes of requests without rigorous resource cleanup protocols. Furthermore, from an offensive security framework perspective, this behavior is consistent with ATT&CK technique T1498, specifically Network Denial of Service via resource exhaustion. The attack vector leverages the legitimate access rights of authorized users to degrade service availability rather than compromising confidentiality or integrity directly.
Mitigation strategies for this vulnerability involve applying vendor-supplied security patches that address the memory management logic within the DHCP server component. Administrators should ensure that all Windows servers running the DHCP role are updated with the latest cumulative updates provided by Microsoft. Additionally, implementing network segmentation can limit the blast radius of such an attack by restricting which subnets or VLANs have direct access to critical DHCP infrastructure. Monitoring system resource usage and setting up alerts for abnormal memory consumption patterns on DHCP servers can also provide early warning signs of potential exploitation attempts, allowing administrators to respond before a full denial of service occurs. Regular auditing of user permissions ensures that only essential personnel retain the ability to interact with sensitive network services, thereby reducing the attack surface available to internal threats.