CVE-2025-70252 is a stack-based buffer overflow vulnerability identified in the Tenda AC6V2.0 router firmware version 15.03.06.23_multi, specifically in the /goform/WifiWpsStart endpoint. The vulnerability stems from improper input validation and lack of boundary checks when handling the 'index' and 'mode' parameters. These parameters are controllable by an attacker and are used in a sprintf function call to concatenate data into a temporary buffer without verifying the buffer size, leading to a classic stack overflow condition (CWE-121). This flaw can be triggered remotely over the network without requiring any authentication or user interaction, as the endpoint is accessible via the router’s web interface. Exploiting this vulnerability can cause the router to crash or reboot, resulting in denial of service (DoS). While no public exploits have been reported yet, the vulnerability’s characteristics make it a prime candidate for future exploitation, especially in automated attacks targeting vulnerable IoT devices. The lack of an available patch at the time of disclosure increases the urgency for network administrators to implement interim protective measures. The vulnerability’s CVSS v3.1 score is 7.5 (high), reflecting its network attack vector, low attack complexity, no privileges required, no user interaction, and impact limited to availability disruption.

The primary impact of CVE-2025-70252 is denial of service against affected Tenda AC6V2.0 routers, which can disrupt network connectivity for individuals and organizations relying on these devices. This can lead to operational downtime, loss of productivity, and potential exposure to further attacks if network segmentation or failover mechanisms are not in place. In environments where these routers serve as critical network gateways, the impact could extend to business continuity and security posture degradation. Additionally, persistent denial of service could be leveraged as part of a larger attack campaign or to distract defenders while other attacks are conducted. Although this vulnerability does not directly compromise confidentiality or integrity, the loss of availability can have cascading effects on dependent systems and services. The ease of exploitation without authentication increases the risk of widespread attacks, especially in poorly secured or exposed network environments.

To mitigate CVE-2025-70252, organizations should first check for firmware updates from Tenda addressing this vulnerability and apply them promptly once available. In the absence of an official patch, administrators should disable the WPS feature if it is not essential, as this reduces the attack surface related to the vulnerable endpoint. Restrict access to the router’s management interface by implementing network segmentation and firewall rules to limit access only to trusted internal networks or VPN connections. Monitoring network traffic for unusual requests to /goform/WifiWpsStart can help detect exploitation attempts. Employing intrusion detection/prevention systems (IDS/IPS) with signatures targeting this vulnerability can provide additional defense. Regularly auditing and updating device firmware and configurations will help prevent exploitation of similar vulnerabilities. Finally, consider replacing affected devices with models from vendors with stronger security track records if long-term support is uncertain.