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 specially crafted network packets sent over the local area network, leading to a stack-based buffer overflow condition (CWE-121). An attacker located on the same LAN can exploit this flaw without requiring any authentication or user interaction, by sending maliciously crafted discovery packets to the vulnerable device. The overflow can cause the device to malfunction, potentially leading to denial of service or enabling further compromise of the device’s confidentiality and integrity. The vulnerability affects firmware versions below V3.7.80, and no patches have been linked yet, indicating that organizations must remain vigilant. The CVSS v3.1 base score is 8.8, reflecting high severity due to the combination of network attack vector, low complexity, no privileges required, and high impact on confidentiality, integrity, and availability. Although no known exploits have been reported in the wild, the critical role of access control devices in physical security environments makes this vulnerability particularly concerning. Exploitation could disrupt access control systems, allowing unauthorized physical access or denial of legitimate access, thereby impacting organizational security posture.

For European organizations, the impact of this vulnerability is significant due to the widespread use of Hikvision access control devices in corporate, governmental, and critical infrastructure facilities. Exploitation could lead to denial of service conditions, preventing legitimate personnel from accessing secured areas, or potentially enabling attackers to bypass physical security controls. This could result in unauthorized physical access, data breaches, or sabotage. The compromise of device integrity and confidentiality could also allow attackers to manipulate access logs or disable alarms, further undermining security. Given the vulnerability requires only LAN access, insider threats or attackers who gain initial network footholds could leverage this flaw to escalate their attack. The disruption of physical security systems can have cascading effects on operational continuity and regulatory compliance, especially in sectors like finance, energy, transportation, and government services. The lack of current patches increases the window of exposure, emphasizing the need for proactive mitigation.

1. Immediately segment networks to isolate Hikvision DS-K1T331 devices from general user LANs, restricting access to trusted management networks only. 2. Implement strict access control lists (ACLs) on switches and routers to limit which devices can send discovery packets to the access control devices. 3. Monitor network traffic for unusual or malformed discovery packets targeting Hikvision devices, using IDS/IPS solutions with custom signatures if necessary. 4. Disable the Search and Discovery feature if it is not essential for operations, reducing the attack surface. 5. Maintain an inventory of all Hikvision devices and their firmware versions to identify vulnerable units. 6. Engage with Hikvision support and subscribe to security advisories to obtain and apply firmware updates promptly once available. 7. Conduct regular security audits and penetration testing focused on physical security systems to detect potential exploitation attempts. 8. Train network and security teams on the specifics of this vulnerability to ensure rapid detection and response.