CVE-2025-11653 is a buffer overflow vulnerability identified in the UTT HiPER 2620G device firmware versions 3.1.0 through 3.1.4. The vulnerability arises from improper handling of the NTPServerIP parameter passed to the strcpy function in the /goform/fNTP file, which does not enforce bounds checking. This allows an attacker to send a specially crafted request remotely to overflow the buffer, potentially overwriting adjacent memory and enabling arbitrary code execution or denial of service. The vulnerability requires no authentication or user interaction, making it remotely exploitable over the network. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:L), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (VC:H/VI:H/VA:H). Despite early notification, the vendor has not issued a patch or mitigation guidance, increasing the urgency for affected organizations to implement compensating controls. While no active exploits have been reported in the wild, the public disclosure of the vulnerability and its high severity score suggest a strong likelihood of exploitation attempts. The vulnerability could allow attackers to gain control over affected devices, disrupt network time synchronization services, or pivot into internal networks, posing a significant risk to operational continuity and security.

For European organizations, the impact of CVE-2025-11653 could be substantial, particularly for those relying on UTT HiPER 2620G devices in network infrastructure, telecommunications, or industrial control systems. Exploitation could lead to unauthorized remote code execution, allowing attackers to compromise device integrity, disrupt time synchronization critical for network operations, or launch denial-of-service attacks. This could cascade into broader network outages, data breaches, or manipulation of time-sensitive processes. Given the lack of vendor response and patches, organizations face prolonged exposure. Critical sectors such as energy, finance, and government services that depend on precise time synchronization and robust network devices are especially vulnerable. The potential for attackers to leverage this vulnerability as a foothold into internal networks raises concerns about confidentiality breaches and further lateral movement. The high CVSS score reflects the severe consequences on confidentiality, integrity, and availability, emphasizing the need for immediate attention.

Until an official patch is released by UTT, European organizations should implement specific mitigations to reduce risk. These include: 1) Restricting network access to the management interface of HiPER 2620G devices by implementing strict firewall rules and network segmentation to limit exposure to trusted hosts only. 2) Deploying intrusion detection/prevention systems (IDS/IPS) with signatures or anomaly detection tuned to identify suspicious requests targeting the /goform/fNTP endpoint or unusual buffer overflow attempts. 3) Monitoring network traffic for unusual NTPServerIP parameter values or malformed packets indicative of exploitation attempts. 4) Applying strict input validation proxies or web application firewalls (WAFs) to sanitize inputs directed at vulnerable endpoints. 5) Conducting thorough asset inventories to identify all affected devices and prioritizing their isolation or replacement if feasible. 6) Engaging with UTT for updates and tracking vulnerability disclosures for patch availability. 7) Preparing incident response plans specifically addressing potential exploitation scenarios involving this vulnerability. These targeted actions go beyond generic advice by focusing on network-level controls, monitoring, and proactive device management tailored to the vulnerability’s characteristics.