CVE-2026-69510 in Windows
Summary
by MITRE • 09/08/2026
Stack-based buffer overflow in Windows DHCP Server allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 09/08/2026
The vulnerability described constitutes a critical security flaw within the Dynamic Host Configuration Protocol (DHCP) server service on Microsoft Windows operating systems, specifically manifesting as a stack-based buffer overflow. This type of memory corruption error occurs when a program writes more data to a fixed-length block of memory stored on the call stack than it is allocated to hold. In the context of the DHCP server, this flaw typically arises during the processing of specially crafted network packets that contain malformed or excessively long option fields. When the service attempts to parse these inputs without adequate bounds checking, the excess data overwrites adjacent memory locations on the stack, including critical control structures such as return addresses and saved frame pointers. This manipulation allows an attacker to redirect the execution flow of the vulnerable process away from its intended path and toward malicious code injected into the same buffer or elsewhere in the process address space.
From a technical perspective, this vulnerability aligns with Common Weakness Enumeration (CWE) identifier CWE-121, which defines stack-based buffer overflow as a weakness where data is written beyond the bounds of a fixed-size stack buffer. The operational impact of such an exploit is severe because it grants unauthorized remote code execution capabilities to any network-accessible attacker who can reach the DHCP server service. By leveraging this flaw, an adversary does not merely gain access to configuration data or disrupt availability; they achieve full control over the underlying operating system with the privileges assigned to the DHCP service account. This often results in complete compromise of the affected host, enabling further lateral movement within the network, installation of backdoors, exfiltration of sensitive information, and potential pivoting to other critical infrastructure components that rely on or trust the compromised DHCP server for address assignment and configuration delivery.
The attack vector associated with this vulnerability is classified under MITRE ATT&CK technique T1059, specifically Command and Scripting Interpreter variants often used in conjunction with remote code execution exploits like T1203, Exploitation for Client Execution. The attacker typically sends a single or series of crafted DHCP packets to the target server over UDP port 67. Because the vulnerability exists within the network-facing service component, no authentication is required prior to exploitation, making it particularly dangerous in environments where the DHCP server is exposed to untrusted networks or lacks proper segmentation. Once executed, the malicious code runs with the context of the system account if the DHCP service is configured to run under high-privilege credentials, which is a common default configuration that exacerbates the risk profile significantly.
Mitigation strategies for this vulnerability primarily involve applying vendor-supplied security patches and updates released by Microsoft to address the specific memory handling deficiencies in the DHCP server codebase. Organizations must ensure that all Windows servers running the DHCP role are promptly updated with the latest cumulative security fixes. In addition to patching, network-level controls should be implemented to restrict access to UDP port 67 only from trusted subnets and authorized clients using firewall rules or Access Control Lists (ACLs). This limits the attack surface by preventing untrusted hosts from sending potentially malicious packets to the service. Furthermore, deploying intrusion detection systems that can identify anomalous DHCP traffic patterns may provide an additional layer of defense against exploitation attempts while patching efforts are underway. Regular auditing of service configurations and adherence to least privilege principles for service accounts also reduces the potential impact if a vulnerability is successfully exploited in other contexts.