CVE-2025-70252 is a stack overflow vulnerability identified in the Tenda AC6V2.0 router firmware version 15.03.06.23_multi. The flaw exists in the /goform/WifiWpsStart endpoint, where two parameters, 'index' and 'mode', are controllable by an attacker. These parameters are incorporated into a temporary buffer via a sprintf call without any bounds checking, which leads to a classic stack-based buffer overflow condition. This lack of size validation allows an attacker to overwrite the stack, potentially enabling arbitrary code execution or causing the device to crash, resulting in denial of service. The vulnerability is exploitable remotely if the attacker can send crafted requests to the vulnerable endpoint, which is typically exposed on the router's web management interface. No authentication is required to trigger the vulnerability, increasing its risk profile. Although no public exploits have been reported yet, the nature of the vulnerability and the popularity of Tenda routers make it a critical concern. The absence of patches or vendor advisories at this time means that affected users must rely on network-level mitigations and monitoring. This vulnerability highlights the risks of improper input validation and unsafe string handling in embedded device firmware.

The impact of CVE-2025-70252 is significant for organizations and individuals using the affected Tenda AC6V2.0 routers. Successful exploitation can lead to arbitrary code execution, allowing attackers to take full control of the device, manipulate network traffic, or pivot to internal networks. This compromises confidentiality, integrity, and availability of network communications. Additionally, a denial of service condition could disrupt internet connectivity for users relying on the router. Since these devices are commonly deployed in home and small office environments, the vulnerability could be leveraged for large-scale botnet recruitment or as a foothold for further attacks within corporate networks. The lack of authentication requirement and remote exploitability increase the likelihood of exploitation, especially in environments where router management interfaces are exposed to untrusted networks. The absence of patches further exacerbates the risk, potentially leading to widespread exploitation once proof-of-concept code becomes available.

1. Immediately restrict access to the router's web management interface by disabling remote management features or limiting access to trusted IP addresses only. 2. Change default credentials to strong, unique passwords to reduce the risk of unauthorized access. 3. Monitor network traffic for unusual or suspicious requests targeting the /goform/WifiWpsStart endpoint. 4. Segment the network to isolate vulnerable devices from critical infrastructure and sensitive data. 5. Regularly check for firmware updates from Tenda and apply patches promptly once available. 6. Consider deploying network intrusion detection/prevention systems (IDS/IPS) that can detect exploitation attempts targeting this vulnerability. 7. If possible, replace affected devices with models from vendors with a stronger security track record until a patch is released. 8. Educate users about the risks of exposing router management interfaces to the internet and encourage best practices for device security.