CVE-2024-0993 is a critical security vulnerability identified in the Tenda i6 router firmware version 1.0.0.9(3857). The flaw exists in the function formWifiMacFilterGet within the httpd component, specifically in the handling of the 'index' argument. This vulnerability is classified as a stack-based buffer overflow (CWE-121), which occurs when the input to the function is manipulated to overwrite the stack memory. Such an overflow can lead to arbitrary code execution, allowing an attacker to potentially take full control of the affected device. The vulnerability is remotely exploitable over the network without requiring user interaction, but it does require high privileges (PR:H) to exploit, indicating that some form of authentication or elevated access is necessary. The CVSS v3.1 base score is 7.2 (high severity), reflecting the significant impact on confidentiality, integrity, and availability if exploited. Although the vendor Tenda was contacted early, there has been no response or patch released to date. The exploit details have been publicly disclosed, increasing the risk of exploitation by threat actors. No known exploits in the wild have been reported yet, but the public availability of the exploit code raises the likelihood of future attacks.

For European organizations, the impact of this vulnerability can be substantial, especially for those relying on Tenda i6 routers in their network infrastructure. Successful exploitation could lead to full compromise of the router, enabling attackers to intercept, modify, or disrupt network traffic, launch further attacks within the internal network, or create persistent backdoors. This could result in data breaches, loss of network availability, and damage to organizational reputation. Critical infrastructure providers, SMEs, and enterprises using these devices without adequate segmentation or monitoring are particularly at risk. The lack of vendor response and patch availability exacerbates the threat, forcing organizations to consider device replacement or mitigations to reduce exposure. Given the router’s role as a network gateway, exploitation could also impact connected IoT devices and internal systems, amplifying the potential damage.

1. Immediate mitigation should include isolating Tenda i6 devices from critical network segments and restricting administrative access to trusted personnel only. 2. Disable remote management interfaces if enabled, to reduce the attack surface. 3. Implement network-level protections such as firewall rules to block unauthorized access to the router’s management ports, especially from external networks. 4. Monitor network traffic for unusual activity that could indicate exploitation attempts. 5. Where possible, replace affected Tenda i6 devices with routers from vendors that provide timely security updates and have a strong security track record. 6. If replacement is not immediately feasible, consider deploying network intrusion detection/prevention systems (IDS/IPS) tuned to detect exploitation attempts targeting this vulnerability. 7. Maintain strict network segmentation to limit lateral movement if a device is compromised. 8. Regularly audit and update credentials to prevent unauthorized access, as exploitation requires high privileges. 9. Stay informed on any future patches or vendor advisories and apply updates promptly once available.