CVE-2025-12595 identifies a buffer overflow vulnerability in the Tenda AC23 router firmware version 16.03.07.52. The flaw exists in the formSetVirtualSer function within the /goform/SetVirtualServerCfg endpoint, which processes input parameters related to virtual server configuration. By manipulating the argument list sent to this function, an attacker can trigger a buffer overflow condition. This type of vulnerability can lead to arbitrary code execution, denial of service, or system instability. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, making it highly dangerous. The CVSS v4.0 score of 8.7 reflects the high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges or user interaction needed. The exploit code has been publicly disclosed, increasing the likelihood of exploitation attempts. Although no active exploitation has been reported, the vulnerability affects a widely used consumer and small business router model, which often lacks robust security controls. The absence of an official patch at the time of disclosure further elevates the risk. Attackers could leverage this vulnerability to gain persistent access to internal networks, intercept or manipulate traffic, or launch further attacks against connected systems.

For European organizations, this vulnerability poses a significant risk to network security and operational continuity. Many small and medium enterprises (SMEs) and home offices use Tenda AC23 routers due to their affordability and features. Exploitation could lead to unauthorized access to internal networks, data breaches, interception of sensitive communications, and potential lateral movement to critical systems. The compromise of routers can also facilitate man-in-the-middle attacks, undermining confidentiality and integrity of data. In sectors such as finance, healthcare, and government, where data protection is paramount, such breaches could result in regulatory penalties under GDPR and damage to reputation. Additionally, disruption of network availability could impact business operations. The public availability of exploit code increases the risk of automated attacks targeting vulnerable devices across Europe. Organizations with remote management enabled on these routers are particularly vulnerable. The lack of a patch at disclosure means organizations must rely on network-level mitigations until firmware updates are released.

1. Immediately restrict remote access to the router’s management interface by disabling WAN-side administration or limiting access to trusted IP addresses. 2. Implement network segmentation to isolate routers from critical infrastructure and sensitive data environments. 3. Monitor network traffic for unusual activity targeting the /goform/SetVirtualServerCfg endpoint or signs of buffer overflow exploitation attempts. 4. Deploy intrusion detection/prevention systems (IDS/IPS) with signatures for this vulnerability once available. 5. Regularly check for firmware updates from Tenda and apply patches promptly when released. 6. If firmware updates are not yet available, consider replacing vulnerable devices with models from vendors with timely security support. 7. Educate IT staff about this vulnerability and ensure incident response plans include steps for router compromise scenarios. 8. Disable unnecessary services and features on the router to reduce the attack surface. 9. Use strong, unique passwords for router administration to prevent unauthorized access. 10. Conduct regular security audits of network devices to identify and remediate vulnerabilities proactively.