CVE-2025-12265 identifies a buffer overflow vulnerability in the Tenda CH22 router firmware version 1.0.0.1. The flaw resides in the fromVirtualSer function, which processes requests to the /goform/VirtualSer endpoint. Specifically, the vulnerability is triggered by manipulating the 'page' argument, which is not properly bounds-checked, leading to a buffer overflow condition. This type of vulnerability can allow an attacker to overwrite memory, potentially enabling arbitrary code execution or denial of service. The vulnerability is remotely exploitable over the network without requiring user interaction or prior authentication, making it highly accessible to attackers. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:L), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (VC:H/VI:H/VA:H). Although no active exploitation has been reported, a public exploit is available, increasing the risk of imminent attacks. The lack of official patches at the time of publication necessitates immediate defensive measures. This vulnerability affects a specific firmware version, so organizations should verify their device versions and apply mitigations accordingly.

For European organizations, the impact of this vulnerability can be substantial. Tenda CH22 routers are often deployed in small to medium enterprise environments and possibly in home office setups, which are increasingly critical due to remote work trends. Successful exploitation could lead to unauthorized access to internal networks, interception or modification of sensitive data, disruption of network services, and potential lateral movement within corporate networks. The confidentiality of communications could be compromised, integrity of data altered, and availability of network resources disrupted, affecting business continuity. Given the remote exploitability and no need for user interaction, attackers could automate attacks at scale, targeting multiple organizations simultaneously. This poses a significant risk to sectors reliant on secure and stable network infrastructure, including finance, healthcare, and government agencies within Europe.

Immediate mitigation steps include verifying the firmware version of all Tenda CH22 devices and isolating or restricting access to vulnerable devices from untrusted networks. Network segmentation should be enforced to limit exposure. Deploy network intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics capable of detecting anomalous requests to /goform/VirtualSer endpoints. Employ strict firewall rules to block unsolicited inbound traffic targeting router management interfaces. Monitor network logs for unusual activity related to the 'page' parameter in HTTP requests. Since no official patch is currently available, organizations should contact Tenda support for guidance and monitor for firmware updates. Where possible, replace vulnerable devices with updated hardware or firmware versions. Additionally, implement strong authentication and management interface access controls to reduce attack surface. Regular vulnerability scanning and penetration testing should be conducted to detect exploitation attempts.