CVE-2024-40416 is a stack-based buffer overflow vulnerability identified in the Tenda AX1806 router firmware version 1.0.0.1. The vulnerability resides in the /goform/SetVirtualServerCfg endpoint, specifically within the sub_6320C function. A buffer overflow occurs when the function improperly handles input data, allowing an attacker to overwrite parts of the stack. This can lead to a denial of service (DoS) condition by crashing the device or potentially enable execution of arbitrary code, although no evidence currently suggests code execution is achievable. The vulnerability can be exploited remotely without requiring authentication or user interaction, but the attacker must have network access to the device’s management interface. The CVSS v3.1 score is 6.5 (medium severity), reflecting the vulnerability’s impact on availability without compromising confidentiality or integrity. No patches or official fixes have been published at this time, and no active exploits have been reported in the wild. The vulnerability is classified under CWE-121, indicating a classic stack-based buffer overflow issue. This type of vulnerability typically arises from unsafe memory operations such as unchecked string or buffer copying. The affected device, Tenda AX1806, is a consumer-grade Wi-Fi 6 router commonly used in residential and small office environments. The vulnerability could be leveraged by attackers to disrupt network connectivity or cause device reboots, impacting network availability.

The primary impact of CVE-2024-40416 is on the availability of affected Tenda AX1806 routers. Successful exploitation can cause the device to crash or reboot, resulting in denial of service for users relying on the router for internet connectivity. This can disrupt business operations, remote work, and critical communications, especially in small offices or home environments where this router is deployed. Although confidentiality and integrity are not directly impacted according to the CVSS vector, repeated or targeted attacks could degrade network reliability and trust in the device. The lack of authentication requirement and user interaction lowers the barrier for attackers with network access to exploit this vulnerability. Since no known exploits are currently in the wild, the immediate risk is moderate, but the potential for future exploitation remains. Organizations using these routers in sensitive or critical environments could face operational disruptions and should prioritize mitigation. Additionally, the vulnerability could be leveraged as part of a larger attack chain to facilitate lateral movement or network reconnaissance if combined with other vulnerabilities.

1. Restrict network access to the router’s management interface by implementing firewall rules or network segmentation to limit exposure to trusted devices only. 2. Disable remote management features if not required, especially WAN-side access to the /goform/SetVirtualServerCfg endpoint. 3. Monitor router logs and network traffic for unusual requests targeting the /goform/SetVirtualServerCfg endpoint or signs of device instability such as unexpected reboots or crashes. 4. Regularly check for firmware updates from Tenda and apply patches promptly once available. 5. Consider replacing affected devices with models from vendors with a stronger security track record if timely patches are not forthcoming. 6. Employ network intrusion detection systems (NIDS) with signatures for buffer overflow attempts targeting Tenda routers to detect exploitation attempts. 7. Educate users about the risks of exposing router management interfaces to untrusted networks and enforce strong network access controls. 8. If possible, implement network-level anomaly detection to identify and block malformed packets that could trigger the buffer overflow.