CVE-2025-9812 is a high-severity buffer overflow vulnerability identified in the Tenda CH22 device, specifically affecting version 1.0.0.1. The vulnerability resides in the function formexeCommand within the /goform/exeCommand endpoint. An attacker can exploit this flaw by manipulating the 'cmdinput' argument, which leads to a buffer overflow condition. This overflow can corrupt memory and potentially allow remote code execution or cause denial of service. The vulnerability is remotely exploitable without requiring user interaction or elevated privileges, making it particularly dangerous. The CVSS 4.0 score of 8.7 reflects its high impact on confidentiality, integrity, and availability, with an attack vector over the network and low attack complexity. Although no public exploits have been observed in the wild yet, the exploit code has been publicly disclosed, increasing the risk of imminent attacks. The vulnerability does not require authentication, and the scope is limited to the affected Tenda CH22 firmware version 1.0.0.1. The lack of available patches at the time of disclosure further elevates the risk for users of this device. Buffer overflow vulnerabilities in network-exposed device management interfaces are critical because they can lead to full device compromise, enabling attackers to pivot into internal networks or disrupt network services.

For European organizations, the impact of this vulnerability can be significant, especially for those relying on Tenda CH22 devices in their network infrastructure. Successful exploitation could lead to unauthorized remote code execution, allowing attackers to gain control over the device, intercept or manipulate network traffic, and potentially launch further attacks within the internal network. This can compromise sensitive data confidentiality and integrity, disrupt business operations through denial of service, and damage organizational reputation. Given the remote and unauthenticated nature of the exploit, attackers could target these devices en masse, leading to widespread network outages or breaches. Organizations in sectors with critical infrastructure or sensitive data, such as finance, healthcare, and government, are particularly at risk. The absence of patches means organizations must rely on mitigations until official fixes are released, increasing exposure duration.

1. Immediate network-level controls: Restrict access to the Tenda CH22 management interface (/goform/exeCommand) by implementing firewall rules or access control lists (ACLs) to allow only trusted IP addresses or internal management networks. 2. Network segmentation: Isolate Tenda CH22 devices from critical network segments to limit lateral movement if compromised. 3. Monitor network traffic for anomalous requests targeting /goform/exeCommand, especially those containing suspicious 'cmdinput' parameters, using intrusion detection/prevention systems (IDS/IPS). 4. Disable remote management interfaces if not required, or restrict them to secure VPN connections. 5. Maintain an inventory of all Tenda CH22 devices and their firmware versions to identify and prioritize vulnerable devices. 6. Engage with Tenda for official patches or firmware updates and apply them promptly once available. 7. Consider deploying endpoint detection and response (EDR) solutions to detect unusual device behavior indicative of exploitation attempts. 8. Educate network administrators about this vulnerability and ensure incident response plans include steps for potential exploitation scenarios.