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 within the /goform/SafeMacFilter endpoint, where improper handling of the 'page' argument allows an attacker to overflow a buffer. This flaw can be exploited remotely without requiring authentication or user interaction, making it highly accessible to attackers. The buffer overflow can lead to arbitrary code execution, allowing attackers to gain control over the affected device, potentially compromising network traffic, injecting malicious payloads, or disrupting network availability. The CVSS 4.0 base score of 8.7 reflects the vulnerability's high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges required. Although no known exploits are currently active in the wild, the public disclosure of exploit code increases the likelihood of exploitation attempts. The vulnerability affects only firmware version 1.0.0.1, and no official patches have been linked yet, emphasizing the need for vigilance and interim mitigations. The vulnerability's presence in a widely used consumer and small business router model raises concerns about the security of networks relying on these devices, especially in environments with limited network segmentation or monitoring.

For European organizations, this vulnerability poses a significant risk to network security and operational continuity. Exploitation could allow attackers to execute arbitrary code on routers, leading to full compromise of network traffic passing through the device. This could result in data interception, unauthorized access to internal systems, lateral movement within corporate networks, and disruption of internet connectivity. Critical infrastructure operators, SMEs, and enterprises using Tenda CH22 routers may experience service outages or data breaches. The vulnerability's remote and unauthenticated nature increases the attack surface, especially for organizations with exposed management interfaces or insufficient network segmentation. Additionally, the public availability of exploit code could lead to rapid exploitation attempts, increasing the urgency for mitigation. The impact extends beyond confidentiality to integrity and availability, potentially affecting business operations and compliance with data protection regulations such as GDPR.

1. Immediate action should focus on obtaining and applying official firmware updates from Tenda once released to address CVE-2025-12234. 2. Until patches are available, restrict access to the router's management interfaces by implementing network segmentation and firewall rules limiting access to trusted IP addresses only. 3. Disable remote management features if not required to reduce exposure. 4. Monitor network traffic for unusual requests targeting the /goform/SafeMacFilter endpoint or anomalous patterns indicative of exploitation attempts. 5. Employ intrusion detection/prevention systems (IDS/IPS) with signatures tuned to detect buffer overflow attempts against Tenda routers. 6. Conduct regular audits of network devices to identify and inventory vulnerable Tenda CH22 routers. 7. Educate IT staff on the vulnerability and ensure incident response plans include steps for potential exploitation scenarios. 8. Consider deploying network segmentation to isolate vulnerable devices from critical assets, minimizing lateral movement risk. 9. Engage with Tenda support channels for timely updates and advisories. 10. For organizations with limited capacity to patch immediately, consider temporary device replacement or use of alternative secure network equipment.