CVE-2025-55605 is a critical buffer overflow vulnerability identified in the Tenda AX3 router firmware version V16.03.12.10_CN. The vulnerability exists within the saveParentControlInfo function, specifically triggered via the deviceName 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, the improper handling of the deviceName input allows an attacker to overflow the buffer, which can lead to arbitrary code execution, denial of service, or system compromise. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). The CVSS score of 9.8 reflects the critical nature of this flaw, with high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). The CWE classification CWE-120 confirms this is a classic buffer overflow issue. Although no known exploits are currently reported in the wild, the ease of exploitation and severity make this a significant threat to any device running the affected firmware. The lack of available patches at the time of publication increases the urgency for mitigation and monitoring. Given that Tenda AX3 routers are consumer and small business networking devices, exploitation could allow attackers to gain control over the router, intercept or manipulate network traffic, or pivot to other devices on the network.

For European organizations, this vulnerability poses a substantial risk, especially for small and medium enterprises (SMEs) and home office environments that commonly use consumer-grade routers like the Tenda AX3. Successful exploitation could lead to full compromise of the router, enabling attackers to intercept sensitive communications, inject malicious traffic, or establish persistent footholds within internal networks. This could result in data breaches, disruption of business operations, and potential lateral movement to more critical infrastructure. The high severity and remote, unauthenticated exploitability mean that attackers can target vulnerable devices en masse, potentially leading to widespread network outages or espionage campaigns. Additionally, given the router's role as a network gateway, compromised devices could be used as launch points for attacks against other European organizations or critical infrastructure, amplifying the threat landscape.

Immediate mitigation steps include: 1) Identifying all Tenda AX3 routers in use within the organization and verifying their firmware version. 2) Applying any available firmware updates from Tenda as soon as they are released; if no patch is available, consider temporarily replacing or isolating affected devices. 3) Restricting remote management access to the router, disabling WAN-side administration interfaces, and limiting access to trusted internal IP addresses. 4) Implementing network segmentation to isolate vulnerable routers from critical systems and sensitive data. 5) Monitoring network traffic for unusual patterns indicative of exploitation attempts, such as unexpected deviceName parameter usage or anomalous packets targeting router management services. 6) Employing intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics tuned to detect buffer overflow attempts against Tenda routers. 7) Educating users and IT staff about the risks and signs of router compromise to enable rapid response. These measures go beyond generic advice by focusing on device-specific controls and proactive detection.