CVE-2025-11653 identifies a critical buffer overflow vulnerability in the UTT HiPER 2620G device firmware versions 3.1.0 through 3.1.4. The vulnerability arises from unsafe use of the strcpy function in the /goform/fNTP endpoint, specifically when processing the NTPServerIP parameter. Because strcpy does not perform bounds checking, an attacker can supply an overly long string to overflow the buffer, potentially overwriting adjacent memory. This can lead to arbitrary code execution or cause the device to crash, impacting availability. The vulnerability is remotely exploitable without requiring authentication or user interaction, increasing the attack surface. The CVSS 4.0 score of 8.7 reflects the high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges needed. The vendor was contacted but has not responded or issued a patch, and public exploit code has been disclosed, increasing the risk of active exploitation. The affected device is commonly used for network time protocol (NTP) synchronization in various enterprise and industrial environments. Exploitation could disrupt time synchronization services, which are critical for logging, security event correlation, and operational processes. The lack of vendor mitigation necessitates immediate defensive measures by users of the affected firmware versions.

For European organizations, this vulnerability could have severe consequences. The UTT HiPER 2620G is often deployed in network infrastructure for time synchronization, which is essential for security event logging, compliance, and operational coordination. Exploitation could allow attackers to execute arbitrary code remotely, potentially gaining control over the device or causing denial of service. This can disrupt critical services, impair forensic investigations, and open pathways for lateral movement within networks. Industrial sectors such as energy, telecommunications, and finance that rely on precise time synchronization are particularly vulnerable. The absence of a vendor patch increases exposure, and public exploit availability raises the likelihood of attacks. Organizations may face operational downtime, data integrity issues, and regulatory compliance risks. The impact extends beyond individual devices to the broader network and business processes dependent on accurate timekeeping.

Given the lack of an official patch, European organizations should implement the following specific mitigations: 1) Immediately identify and inventory all UTT HiPER 2620G devices running affected firmware versions. 2) Restrict network access to the /goform/fNTP endpoint by applying firewall rules or access control lists to limit exposure to trusted management networks only. 3) Disable or restrict NTP configuration interfaces if possible to prevent remote manipulation of the NTPServerIP parameter. 4) Employ network segmentation to isolate vulnerable devices from critical infrastructure and sensitive networks. 5) Monitor network traffic and device logs for unusual activity targeting the NTP service or signs of buffer overflow exploitation attempts. 6) Consider deploying intrusion detection/prevention systems with signatures for this vulnerability or related exploit patterns. 7) Engage with UTT or third-party vendors for alternative firmware or mitigation guidance. 8) Plan for device replacement or firmware upgrade once a patch becomes available. 9) Enhance incident response readiness to quickly address potential exploitation. These targeted steps go beyond generic advice by focusing on controlling access to the vulnerable function and monitoring for exploitation.