CVE-2025-66176 is a stack overflow vulnerability identified in the Search and Discovery feature of the Hikvision DS-K1T331 access control device. This vulnerability arises due to improper handling of network packets during the device discovery process, allowing an attacker on the same local area network to send specially crafted packets that overflow the stack memory. The overflow can lead to device malfunction, which may include crashes, denial of service, or potentially arbitrary code execution depending on the device's memory protections and exploit complexity. The vulnerability affects firmware versions below V3.7.80, and no authentication or user interaction is required to exploit it, making it accessible to any attacker with LAN access. The CVSS v3.1 score of 8.8 reflects a high severity due to the combination of network attack vector (local), low attack complexity, no privileges required, and impacts to confidentiality, integrity, and availability. Although no public exploits have been reported yet, the nature of the vulnerability and the widespread use of Hikvision devices in physical security contexts make this a critical concern. The device malfunction could disrupt physical access controls, potentially allowing unauthorized access or denial of legitimate access, thereby compromising security operations.

For European organizations, the impact of this vulnerability is significant, especially for those relying on Hikvision DS-K1T331 devices for physical access control in sensitive environments such as government buildings, transportation hubs, healthcare facilities, and critical infrastructure. Exploitation could lead to denial of service of access control systems, causing operational disruptions and potential security breaches. Confidentiality could be compromised if attackers leverage the malfunction to intercept or manipulate access logs or credentials. Integrity of access control policies may be undermined, allowing unauthorized physical access or tampering with device configurations. Availability is directly affected as the device may crash or become unresponsive. Given the local network attack vector, organizations with poor network segmentation or insufficient internal network security controls are at higher risk. The disruption of physical security systems could have cascading effects on safety, compliance, and business continuity.

To mitigate this vulnerability, European organizations should immediately update all affected Hikvision DS-K1T331 devices to firmware version V3.7.80 or later, where the vulnerability is patched. Network segmentation should be enforced to isolate access control devices from general user networks, limiting attacker access to the local network segment. Implement strict access controls and monitoring on the LAN to detect anomalous packet activity targeting device discovery protocols. Employ network intrusion detection/prevention systems (IDS/IPS) tuned to identify malformed packets or unusual traffic patterns associated with this vulnerability. Regularly audit and inventory physical security devices to ensure all are running supported and patched firmware versions. Additionally, consider disabling or restricting the Search and Discovery feature if it is not essential for operations. Establish incident response procedures specific to physical security device compromise to quickly address potential exploitation.