CVE-2025-55613 is a buffer overflow vulnerability identified in the Tenda O3V2 device firmware version 1.0.0.12(3880). The flaw exists in the fromSafeSetMacFilter function, which processes the 'mac' parameter. Buffer overflow vulnerabilities occur when a program writes more data to a buffer than it can hold, potentially overwriting adjacent memory. In this case, improper handling of the 'mac' parameter input allows an attacker to overflow the buffer, which can lead to arbitrary code execution, denial of service, or system instability. The vulnerability is located in a network device firmware, which typically operates with elevated privileges and network exposure, increasing the risk. No CVSS score has been assigned yet, and no known exploits have been reported in the wild. The affected version is specifically 1.0.0.12(3880), with no other versions explicitly listed. The lack of patch links suggests that no official fix has been publicly released at the time of this report. Because the vulnerability involves a network-facing function related to MAC filtering, it could be exploited remotely if the device's management interface is accessible, potentially without authentication if the function is exposed. This elevates the risk of exploitation in environments where these devices are deployed without adequate network segmentation or access controls.

For European organizations, the impact of this vulnerability could be significant, especially for those relying on Tenda O3V2 devices in their network infrastructure. Exploitation could allow attackers to execute arbitrary code on the device, leading to full compromise of the network device. This could result in unauthorized network access, interception or manipulation of network traffic, disruption of network services, and potential pivoting to other internal systems. Given that network devices are critical for maintaining connectivity and security boundaries, a successful attack could degrade availability and compromise confidentiality and integrity of organizational data. Industries with high reliance on network stability and security, such as finance, healthcare, and critical infrastructure, may face operational disruptions and data breaches. Additionally, the absence of a patch increases the window of exposure, necessitating immediate mitigation efforts. The threat is heightened in environments where devices are accessible from less trusted networks or where default configurations have not been hardened.

Organizations should immediately identify and inventory all Tenda O3V2 devices running firmware version 1.0.0.12(3880). Until a patch is available, network segmentation should be enforced to isolate these devices from untrusted networks, including the internet. Access to device management interfaces should be restricted using firewalls and access control lists, allowing only trusted administrative hosts. Implement strong authentication mechanisms and change default credentials to reduce unauthorized access risk. Monitoring network traffic for unusual activity related to these devices can help detect exploitation attempts. If possible, disable or restrict the use of the MAC filtering feature or the vulnerable function until a patch is released. Organizations should engage with Tenda support channels to obtain updates on patch availability and apply firmware updates promptly once released. Additionally, consider deploying intrusion detection/prevention systems with signatures targeting buffer overflow attempts against Tenda devices. Regular backups of device configurations should be maintained to facilitate recovery in case of compromise.