CVE-2025-12234 is a buffer overflow vulnerability identified in the Tenda CH22 router firmware version 1.0.0.1. The vulnerability resides in the fromSafeMacFilter function within the /goform/SafeMacFilter endpoint. Specifically, the issue arises from improper handling of the 'page' argument, which an attacker can manipulate to overflow a buffer. This buffer overflow can potentially allow an attacker to execute arbitrary code remotely, leading to full compromise of the device. The vulnerability requires no authentication or user interaction, making it highly exploitable over the network. The CVSS 4.0 base score is 8.7, reflecting its critical impact on confidentiality, integrity, and availability, combined with ease of exploitation. The vulnerability affects only the specified firmware version, and no official patches have been released yet. Although no known exploits are currently active in the wild, public disclosure of exploit code increases the urgency for mitigation. The flaw could be leveraged to disrupt network operations, intercept or manipulate traffic, or pivot into internal networks, posing significant risks to organizations relying on Tenda CH22 devices.

The impact of CVE-2025-12234 is substantial for organizations using Tenda CH22 routers, as successful exploitation can lead to remote code execution, enabling attackers to take full control of the device. This compromises the confidentiality of network traffic, integrity of device configurations, and availability of network services. Attackers could disrupt business operations, intercept sensitive communications, or use compromised routers as footholds for further attacks within corporate or governmental networks. Given the device's role as a network gateway, the vulnerability could facilitate lateral movement and data exfiltration. The lack of authentication and user interaction requirements increases the risk of widespread exploitation, especially in environments where these devices are exposed to untrusted networks or the internet. The public availability of exploit code further elevates the threat level, potentially leading to targeted attacks or automated scanning and exploitation campaigns.

Organizations should immediately implement network-level controls to restrict access to Tenda CH22 devices, such as firewall rules limiting management interface exposure to trusted IP addresses only. Disabling remote management features or restricting them to secure VPN connections can reduce attack surface. Continuous monitoring of network traffic for anomalous requests targeting /goform/SafeMacFilter or unusual buffer overflow indicators is recommended. Network segmentation should be enforced to isolate vulnerable devices from critical infrastructure. Since no official patches are currently available, organizations should engage with Tenda support for updates and advisories. Where possible, upgrading to newer, unaffected firmware versions or replacing vulnerable devices with more secure alternatives is advised. Incident response plans should include detection and remediation procedures for exploitation attempts. Additionally, applying intrusion prevention systems (IPS) signatures targeting this vulnerability can help block exploit attempts.