CVE-2022-44362 is a critical buffer overflow vulnerability identified in the Tenda i21 router firmware version V1.0.0.14(4656). The vulnerability exists in the handling of requests to the /goform/AddSysLogRule endpoint. Specifically, the buffer overflow (CWE-787) occurs when the device improperly processes input data, allowing an attacker to overwrite memory beyond the intended buffer boundaries. This can lead to arbitrary code execution, complete compromise of the device, or denial of service. The vulnerability is remotely exploitable over the network without requiring any authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). The impact on confidentiality, integrity, and availability is high, as successful exploitation could allow an attacker to execute arbitrary commands, manipulate system logs, disrupt device operation, or pivot into internal networks. Although no public exploits have been reported in the wild to date, the high CVSS score of 9.8 reflects the severe risk posed by this flaw. The lack of vendor or product details beyond the Tenda i21 model limits the scope of affected devices, but the router is commonly used in small office and home environments. The vulnerability highlights the importance of secure input validation in embedded network devices and the risks posed by exposed management interfaces.

For European organizations, this vulnerability poses a significant threat, especially to small and medium enterprises (SMEs) and home office setups that rely on Tenda i21 routers for internet connectivity. Exploitation could lead to network compromise, data interception, and lateral movement within corporate networks. Given the router’s role as a gateway device, attackers could intercept sensitive communications, inject malicious traffic, or disrupt business operations through denial of service. The vulnerability also risks undermining trust in network infrastructure and could facilitate broader attacks such as ransomware or espionage campaigns. Critical infrastructure sectors that use these routers for remote sites or branch offices may face operational disruptions. The absence of authentication requirements means that attackers can exploit this vulnerability remotely without prior access, increasing the attack surface. Although no known exploits are currently active, the high severity and ease of exploitation necessitate urgent attention to prevent potential future attacks.

1. Immediate mitigation should include isolating affected Tenda i21 devices from untrusted networks to reduce exposure. 2. Network administrators should implement strict firewall rules to block external access to the router’s management interfaces, particularly the /goform/AddSysLogRule endpoint if possible. 3. Monitor network traffic for unusual requests targeting the router’s management URLs or signs of buffer overflow exploitation attempts. 4. If available, update the router firmware to a patched version provided by Tenda; if no patch exists, consider replacing the device with a more secure alternative. 5. Employ network segmentation to limit the impact of a compromised router on critical internal systems. 6. Use intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics designed to detect exploitation attempts of this vulnerability. 7. Educate users and IT staff about the risks of using outdated or unsupported network equipment and encourage regular security assessments of network devices. These steps go beyond generic advice by focusing on network-level controls and monitoring specific to the vulnerable endpoint and device type.