CVE-2025-12234 is a buffer overflow vulnerability identified in the Tenda CH22 router firmware version 1.0.0.1. The vulnerability exists in the fromSafeMacFilter function located in the /goform/SafeMacFilter file, where improper validation and handling of the 'page' argument allows an attacker to overflow a buffer. This flaw can be triggered remotely without requiring authentication or user interaction, making it highly exploitable over the network. The buffer overflow can lead to arbitrary code execution or cause the device to crash, resulting in denial of service. The vulnerability has been assigned a CVSS 4.0 score of 8.7, reflecting its high impact on confidentiality, integrity, and availability. The attack vector is network-based with low attack complexity and no privileges required. Although no known exploits are currently active in the wild, the public disclosure of the exploit code increases the risk of exploitation. The affected product, Tenda CH22, is typically used in consumer and small business environments, which may lack robust security controls. The vulnerability's exploitation could allow attackers to gain control over the router, intercept or manipulate network traffic, or disrupt network connectivity. The lack of available patches at the time of disclosure necessitates immediate mitigation efforts to prevent exploitation.

For European organizations, this vulnerability poses a significant threat, particularly to small and medium enterprises and home office setups that utilize Tenda CH22 routers. Successful exploitation could lead to unauthorized remote control of network devices, enabling attackers to intercept sensitive communications, manipulate data, or disrupt network services. This could compromise confidentiality and integrity of organizational data and impact availability of critical network infrastructure. Given the router's role as a gateway device, attackers could pivot to internal networks, escalating the severity of potential breaches. The absence of authentication and user interaction requirements lowers the barrier for exploitation, increasing risk. Additionally, disruption of network connectivity could affect business operations, especially in sectors relying on continuous internet access. The public disclosure of exploit code further elevates the threat landscape, necessitating urgent attention from affected entities.

1. Immediately monitor network traffic for suspicious requests targeting the /goform/SafeMacFilter endpoint, particularly those manipulating the 'page' parameter. 2. Implement network-level access controls such as firewall rules or intrusion prevention systems (IPS) to block or rate-limit traffic to the vulnerable endpoint. 3. Isolate Tenda CH22 devices from critical network segments to limit potential lateral movement in case of compromise. 4. Regularly check for and apply firmware updates from Tenda as soon as patches addressing CVE-2025-12234 become available. 5. Employ network segmentation and strong authentication mechanisms for device management interfaces to reduce exposure. 6. Conduct vulnerability scanning and penetration testing focused on router firmware to identify similar issues proactively. 7. Educate users and administrators about the risks of using outdated router firmware and the importance of timely updates. 8. Consider replacing vulnerable devices with models from vendors with stronger security track records if patches are delayed or unavailable.