CVE-2025-15234 identifies a heap-based buffer overflow vulnerability in the Tenda M3 router firmware version 1.0.0.13(4903). The flaw exists in the formSetRemoteInternetLanInfo function located in the /goform/setInternetLanInfo endpoint, which processes parameters including portIp, portMask, portGateWay, portDns, and portSecDns. Improper handling and validation of these parameters allow an attacker to overflow the heap buffer by sending specially crafted requests remotely. This vulnerability does not require authentication or user interaction, making it highly exploitable over the network. The heap overflow can lead to memory corruption, enabling attackers to execute arbitrary code with elevated privileges or cause a denial of service by crashing the device. The CVSS 4.0 score of 8.7 reflects the high impact on confidentiality, integrity, and availability, combined with low attack complexity and no required privileges. Although no active exploitation has been reported, a public exploit is available, increasing the risk of future attacks. The vulnerability affects a widely deployed consumer and small business router model, which is often used in home and office environments, potentially exposing many users to compromise if the device is accessible from untrusted networks. The absence of vendor patches at the time of publication necessitates immediate mitigation through network controls and monitoring.

For European organizations, this vulnerability poses significant risks, particularly for small and medium enterprises or home office setups relying on Tenda M3 routers. Successful exploitation could lead to unauthorized remote code execution, allowing attackers to gain control over network traffic, intercept sensitive data, or pivot to internal systems. The integrity and availability of network services could be compromised, disrupting business operations. Given the router’s role as a gateway device, attackers could establish persistent footholds or launch further attacks against connected devices. The lack of authentication and user interaction requirements increases the likelihood of automated exploitation attempts, especially if management interfaces are exposed to the internet. Critical infrastructure sectors using these routers without adequate segmentation or firewall protections may face elevated risks. Additionally, the public availability of an exploit increases the urgency for European organizations to assess their exposure and implement mitigations promptly.

1. Immediately restrict remote access to the router’s management interfaces by disabling WAN-side administration or limiting access via IP whitelisting and VPNs. 2. Monitor network traffic for unusual requests targeting /goform/setInternetLanInfo or abnormal parameter patterns indicative of exploitation attempts. 3. Deploy network intrusion detection/prevention systems (IDS/IPS) with signatures tailored to detect this specific exploit. 4. Segment networks to isolate vulnerable routers from critical assets and sensitive data. 5. Regularly audit and inventory network devices to identify all Tenda M3 routers running the affected firmware version. 6. Engage with Tenda support channels to obtain firmware updates or patches as soon as they become available. 7. If patching is delayed, consider replacing vulnerable devices with models from vendors with timely security updates. 8. Educate IT staff on the risks of exposed router management interfaces and enforce strict configuration baselines. 9. Implement strong logging and alerting mechanisms to detect exploitation attempts early. 10. Review and harden router configurations, disabling unnecessary services and features that increase attack surface.