CVE-2025-4867 is a high-severity vulnerability affecting the Tenda A15 router, specifically version 15.13.07.13. The flaw resides in the function formArpNerworkSet within the /goform/ArpNerworkSet endpoint. This vulnerability allows an unauthenticated remote attacker to manipulate the ARP network settings via crafted requests, leading to a denial of service (DoS) condition. The attack vector is network-based (AV:N), requiring no user interaction (UI:N) and no privileges (PR:L) beyond limited access, which likely corresponds to access to the router’s management interface or exposed service. The vulnerability does not impact confidentiality or integrity but severely affects availability (VA:H), causing service disruption. The CVSS 4.0 base score is 7.1, indicating a high severity. Although no public exploit is currently known to be actively used in the wild, the exploit details have been disclosed publicly, increasing the risk of exploitation. The vulnerability’s root cause is improper handling of ARP network configuration inputs, which can be exploited to crash or destabilize the device, rendering it unusable or forcing a reboot. This can disrupt network connectivity for all devices relying on the affected router, impacting business operations and user productivity.

For European organizations, this vulnerability poses a significant risk to network availability, especially for small and medium enterprises or home office setups that rely on Tenda A15 routers for internet connectivity. A successful DoS attack could interrupt critical communications, delay business processes, and cause downtime. In sectors such as finance, healthcare, and manufacturing, where continuous network availability is crucial, such disruptions could lead to operational losses and regulatory compliance issues. Additionally, since the attack can be launched remotely without authentication, threat actors could target exposed routers across Europe, potentially leveraging this vulnerability as part of larger distributed denial of service (DDoS) campaigns or lateral movement within compromised networks. The lack of confidentiality or integrity impact limits data breach concerns, but the availability impact alone is sufficient to cause significant operational harm.

Organizations should immediately verify if they are using Tenda A15 routers running firmware version 15.13.07.13. If so, they should seek firmware updates or patches from Tenda as a priority, even though no patch links are currently provided, monitoring vendor advisories closely. In the interim, network administrators should restrict access to the router’s management interface by implementing network segmentation and firewall rules to limit access only to trusted internal IP addresses. Disabling remote management features on the router can reduce exposure. Employing intrusion detection systems (IDS) to monitor for suspicious requests targeting /goform/ArpNerworkSet can help detect exploitation attempts. Network operators should also consider replacing vulnerable devices with models that have active security support. Regularly auditing network devices for outdated firmware and enforcing strict access controls will reduce the attack surface. Finally, organizations should prepare incident response plans to quickly restore network services in case of a DoS attack exploiting this vulnerability.