CVE-2025-12265 is a buffer overflow vulnerability identified in the Tenda CH22 router firmware version 1.0.0.1. The flaw exists in the fromVirtualSer function, which processes requests to the /goform/VirtualSer endpoint. Specifically, the vulnerability arises from improper handling of the 'page' argument, allowing an attacker to overflow a buffer by sending crafted input. This buffer overflow can lead to memory corruption, enabling remote code execution or denial of service. The vulnerability is remotely exploitable over the network without requiring user interaction or elevated privileges, making it particularly dangerous. The CVSS v4.0 score of 8.7 reflects the ease of exploitation (attack vector network, low complexity), no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. Although no confirmed active exploitation has been reported, the public availability of exploit code significantly raises the risk of attacks. The vulnerability affects only version 1.0.0.1 of the Tenda CH22 device, a consumer and small business router. The lack of an official patch at the time of disclosure increases exposure. Attackers could leverage this vulnerability to gain unauthorized access, execute arbitrary commands, disrupt network services, or pivot within affected networks. The vulnerability's presence in a network device makes it a critical concern for organizations relying on Tenda CH22 for connectivity and security.

For European organizations, exploitation of CVE-2025-12265 could lead to severe consequences including unauthorized remote code execution on network routers, resulting in full compromise of network traffic, interception of sensitive data, and disruption of network availability. This could affect confidentiality by exposing internal communications, integrity by allowing attackers to alter network configurations or data flows, and availability by causing router crashes or denial of service. Small and medium enterprises (SMEs) and home office environments using Tenda CH22 devices are particularly vulnerable due to potentially weaker network defenses. Critical infrastructure sectors relying on these devices for connectivity could face operational disruptions. The public release of exploit code increases the likelihood of opportunistic attacks, including automated scanning and exploitation by cybercriminals or state-sponsored actors. The vulnerability could also be leveraged as a foothold for lateral movement within corporate networks, escalating the overall risk posture. Given the network-exposed nature of the flaw, attackers do not require physical access or user interaction, heightening the threat level.

Immediate mitigation should focus on obtaining and applying any available firmware updates from Tenda addressing this vulnerability. If no patch is yet available, organizations should implement network-level controls such as restricting access to the management interface of Tenda CH22 devices to trusted IP addresses only, ideally via VPN or internal network segmentation. Deploy intrusion detection and prevention systems (IDS/IPS) with signatures tuned to detect exploitation attempts targeting /goform/VirtualSer or anomalous buffer overflow patterns. Disable or restrict remote management features on the affected devices to minimize exposure. Regularly monitor network traffic and device logs for signs of exploitation attempts. Consider replacing Tenda CH22 devices with more secure alternatives if timely patching is not feasible. Additionally, enforce strong network segmentation to limit the impact of a compromised router and maintain up-to-date asset inventories to quickly identify affected devices. Educate IT staff about this vulnerability and the importance of rapid response to emerging threats.