CVE-2026-69809 in Windows
Summary
by MITRE • 09/09/2026
Missing release of memory after effective lifetime in Active Directory Domain Services allows an unauthorized attacker to deny service over a network.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified as a missing release of memory after its effective lifetime within Microsoft Windows Active Directory Domain Services represents a critical resource management flaw that can be exploited by unauthenticated attackers to cause a denial of service condition. This issue stems from improper handling of allocated memory blocks during the processing of specific network requests directed at domain controllers. When an attacker sends specially crafted packets to the affected system, the underlying code fails to properly deallocate or release the memory resources associated with those operations after they have completed their intended function. Over time, as these malformed requests are processed repeatedly, the cumulative effect is a progressive exhaustion of available system memory on the targeted domain controller.
From a technical perspective, this flaw aligns closely with CWE-401, which describes missing release of memory after effective lifetime. In the context of Active Directory Domain Services, the service handles numerous concurrent connections and authentication requests. The failure to free up memory in specific code paths means that each malicious request consumes additional resources without returning them to the operating system's pool. This leads to a gradual increase in memory usage by the lsass.exe process or related domain services, eventually causing the system to run out of virtual address space or physical RAM. Once these limits are reached, the service may become unresponsive, crash, or force a reboot, thereby disrupting authentication and directory replication processes across the network infrastructure.
The operational impact of this vulnerability is severe for organizations relying on Active Directory for identity management and access control. An unauthorized attacker who can reach the domain controller over the network does not need valid credentials to exploit this flaw. By continuously sending crafted requests that trigger the memory leak, an adversary can effectively degrade or completely halt the availability of critical directory services. This denial of service affects all users and systems dependent on the compromised domain controller for logins, group policy application, and resource access. In a large enterprise environment, such disruption can lead to significant productivity losses and potential security gaps if fallback authentication mechanisms are not in place.
This type of vulnerability is often categorized within the MITRE ATT&CK framework under techniques related to Resource Hijacking or Denial of Service, specifically focusing on exhausting system resources rather than executing arbitrary code. The lack of proper memory management highlights a gap in defensive coding practices where input validation and resource lifecycle tracking are insufficiently enforced. To mitigate this risk, administrators must ensure that all security updates provided by Microsoft for Active Directory Domain Services are promptly applied. These patches typically include fixes to the underlying C++ or native code routines responsible for handling network packets, ensuring that memory is correctly released regardless of whether the input data is valid or malformed. Additionally, implementing network segmentation and restricting direct access to domain controllers from untrusted networks can reduce the attack surface available to potential adversaries attempting to exploit this flaw.