CVE-2025-12225 is a stack-based buffer overflow vulnerability identified in the Tenda AC6 router firmware version 15.03.06.50. The vulnerability exists in the HTTP request handler component, specifically in the processing of the 'shareSpeed' parameter submitted to the /goform/WifiGuestSet endpoint. Improper input validation or bounds checking on this parameter allows an attacker to overflow the stack buffer, potentially overwriting the return address or other control data. This can lead to arbitrary code execution with the privileges of the HTTP handler process. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, making it highly dangerous. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P) indicates network attack vector, low attack complexity, no authentication required, and high impact on confidentiality, integrity, and availability. Although no confirmed exploits in the wild have been reported, the public disclosure of exploit details increases the risk of imminent attacks. The lack of available patches at the time of disclosure necessitates immediate mitigation steps. The vulnerability affects only the specified firmware version, so organizations should verify their device versions and plan for firmware upgrades or device replacement. The Tenda AC6 is commonly deployed in SOHO environments, making it a target for attackers seeking to compromise home or small business networks to pivot into larger organizational environments.

For European organizations, this vulnerability poses a significant risk, especially for those relying on Tenda AC6 routers in home offices or small branch offices. Successful exploitation could allow attackers to execute arbitrary code remotely, leading to full compromise of the device. This can result in interception or manipulation of network traffic, unauthorized access to internal resources, or use of the compromised router as a foothold for lateral movement within corporate networks. Confidentiality is at risk due to potential data interception, integrity can be compromised by malicious configuration changes or injected code, and availability may be affected through device crashes or denial-of-service conditions. Given the remote and unauthenticated nature of the exploit, attackers can launch attacks at scale, increasing the threat to European networks. The impact is heightened by the widespread use of Tenda devices in residential and small business settings, which often have weaker security controls and are less monitored than enterprise-grade equipment.

1. Immediate inventory and identification of Tenda AC6 devices running firmware version 15.03.06.50 within the network. 2. Apply vendor-provided firmware updates as soon as they become available; if no patch is currently released, contact Tenda support for guidance or consider device replacement. 3. Restrict access to the router management interface and the /goform/WifiGuestSet endpoint by implementing network segmentation and firewall rules that limit inbound connections to trusted IP addresses only. 4. Disable remote management features on Tenda AC6 devices if not required, reducing exposure to external attackers. 5. Monitor network traffic for unusual HTTP requests targeting the /goform/WifiGuestSet path and anomalous behavior indicative of exploitation attempts. 6. Employ intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics capable of detecting buffer overflow attempts against Tenda devices. 7. Educate users about the risks of using outdated router firmware and encourage regular updates. 8. Consider deploying network-level security controls such as VPNs or zero-trust architectures to reduce direct exposure of SOHO devices.