CVE-2025-15217 is a buffer overflow vulnerability identified in the Tenda AC23 router firmware version 16.03.07.52. The vulnerability resides in the function formSetPPTPUserList within the HTTP POST request handler component. By manipulating the argument list sent to this function, an attacker can trigger a buffer overflow condition. This flaw is exploitable remotely over the network without requiring authentication or user interaction, increasing the attack surface significantly. The buffer overflow can lead to arbitrary code execution or cause the device to crash, resulting in denial of service. The CVSS 4.0 base score of 8.7 reflects the high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges or user interaction needed. No patches or known exploits have been reported yet, but the vulnerability's nature suggests it could be leveraged for persistent compromise or lateral movement within affected networks. The Tenda AC23 is a consumer and small business router, often deployed in home and office environments, making it a potential entry point for attackers targeting network infrastructure.

For European organizations, exploitation of this vulnerability could lead to unauthorized remote code execution on affected routers, compromising network perimeter security. Attackers could intercept, modify, or disrupt network traffic, leading to data breaches or service outages. Small and medium enterprises relying on Tenda AC23 devices for VPN or PPTP user management are particularly at risk. The disruption of router functionality could cause denial of service, impacting business continuity. Additionally, compromised routers could be used as footholds for further attacks against internal networks or as part of botnets. The lack of authentication requirement and remote exploitability increase the likelihood of widespread attacks if exploit code becomes available. Critical infrastructure and organizations with remote access needs may face heightened risks due to potential exposure of sensitive communications.

Immediate mitigation should focus on restricting remote access to the router's management interface, especially blocking HTTP POST requests targeting the vulnerable function. Network segmentation and firewall rules should be implemented to limit exposure of Tenda AC23 devices to untrusted networks. Monitoring network traffic for anomalous POST requests or unusual router behavior can help detect exploitation attempts. Organizations should prioritize obtaining and applying firmware updates from Tenda once patches are released. In the absence of official patches, consider temporary replacement of affected devices or disabling PPTP user list management features if feasible. Employing intrusion detection/prevention systems (IDS/IPS) with signatures targeting this vulnerability can provide additional defense. Regularly auditing router configurations and access logs will help identify potential compromise early.