CVE-2025-15229 is a denial of service vulnerability identified in the Tenda CH22 router models running firmware versions 1.0.0.0 and 1.0.0.1. The vulnerability resides in the fromDhcpListClient function, specifically in the handling of the LISTLEN argument within the /goform/DhcpListClient endpoint. An attacker can remotely send crafted requests manipulating this argument to cause the router to crash or become unresponsive, effectively denying service to legitimate users. The vulnerability requires no authentication or user interaction, allowing attackers to exploit it over the network with low complexity. The CVSS 4.0 base score is 6.9 (medium severity), reflecting the impact on availability without compromising confidentiality or integrity. Although no exploits are currently reported in the wild, the public disclosure of the exploit code increases the risk of exploitation. The affected endpoint is part of the router's DHCP client list management, and disruption here can interrupt network connectivity for all devices relying on the router. The vulnerability does not affect other components or require privileged access, making it a straightforward attack vector for remote denial of service. No official patches have been linked yet, so mitigation relies on network controls and monitoring. The vulnerability highlights the importance of securing IoT and networking devices that are often overlooked but critical for organizational network availability.

For European organizations, this vulnerability poses a risk primarily to network availability. Disruption of Tenda CH22 routers can lead to loss of internet connectivity, impacting business operations, communications, and access to cloud services. Small and medium enterprises (SMEs) and home office setups that rely on these routers are particularly vulnerable, as they may lack redundant network infrastructure. Critical services dependent on continuous connectivity could experience downtime, resulting in productivity loss and potential financial impact. Additionally, denial of service attacks could be leveraged as part of larger multi-vector attacks or to create distractions while other attacks are conducted. The lack of authentication requirement means attackers can launch attacks from outside the network, increasing exposure. European organizations with remote or distributed workforces using these devices are at heightened risk. The absence of patches at the time of disclosure means organizations must rely on interim mitigations, increasing operational burden. Overall, the impact is moderate but significant enough to warrant prompt attention to avoid service interruptions.

1. Monitor Tenda’s official channels for firmware updates addressing CVE-2025-15229 and apply patches immediately upon release. 2. Restrict access to router management interfaces by implementing network segmentation and firewall rules to limit exposure to trusted IP addresses only. 3. Deploy intrusion detection/prevention systems (IDS/IPS) capable of identifying and blocking malformed requests targeting the /goform/DhcpListClient endpoint or suspicious DHCP-related traffic. 4. Disable remote management features on Tenda CH22 routers if not required, reducing the attack surface. 5. Regularly audit network devices for outdated firmware and replace unsupported hardware where feasible. 6. Educate IT staff and users about the risks of using vulnerable routers and encourage reporting of connectivity issues that may indicate exploitation attempts. 7. Consider network redundancy or failover solutions to maintain connectivity in case of router failure. 8. Implement logging and monitoring to detect unusual traffic patterns indicative of denial of service attempts targeting the router.