CVE-2025-11122 is a high-severity stack-based buffer overflow vulnerability affecting the Tenda AC18 router, specifically version 15.03.05.19. The vulnerability resides in an unspecified function within the /goform/WizardHandle endpoint, where improper handling of the 'WANT/mtuvalue' argument allows an attacker to overflow the stack buffer. This flaw can be exploited remotely without requiring user interaction or prior authentication, as indicated by the CVSS vector (AV:N/AC:L/AT:N/UI:N/PR:L). The vulnerability’s exploitation can lead to severe consequences including arbitrary code execution with elevated privileges, potentially allowing full control over the device. The public availability of an exploit increases the risk of active attacks. The vulnerability impacts the confidentiality, integrity, and availability of the affected device, as attackers could intercept or manipulate network traffic, disrupt network services, or use the compromised router as a foothold for further attacks within the network. The lack of a patch link suggests that no official fix has been released yet, increasing the urgency for mitigation. Given the router’s role as a network gateway, exploitation could have cascading effects on connected systems and data.

For European organizations, the impact of this vulnerability can be significant. Tenda AC18 routers are commonly used in small to medium enterprises and home office environments due to their cost-effectiveness and feature set. A successful exploit could lead to unauthorized access to internal networks, data interception, or lateral movement by attackers. This is particularly critical for organizations handling sensitive personal data under GDPR, as breaches could result in regulatory penalties and reputational damage. The vulnerability’s remote exploitability without user interaction means that attackers can target exposed devices directly over the internet, increasing the risk of widespread compromise. Additionally, compromised routers can be leveraged for launching distributed denial-of-service (DDoS) attacks or as part of botnets, further impacting network availability and organizational operations. The absence of an official patch increases the window of exposure, necessitating immediate defensive actions to protect European networks.

Given the absence of an official patch, European organizations should implement several specific mitigation strategies: 1) Immediately audit network infrastructure to identify Tenda AC18 devices running the vulnerable firmware version 15.03.05.19. 2) If possible, isolate affected devices from direct internet exposure by placing them behind additional firewalls or VPNs to restrict access to the /goform/WizardHandle endpoint. 3) Disable remote management features on the router to prevent external exploitation vectors. 4) Employ network intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics aimed at detecting exploitation attempts targeting this vulnerability. 5) Monitor network traffic for unusual patterns or spikes that may indicate exploitation attempts or successful compromise. 6) Engage with Tenda support channels to obtain information on forthcoming patches or firmware updates and plan for prompt deployment once available. 7) As a longer-term measure, consider replacing vulnerable devices with routers from vendors with strong security update policies and proven track records. 8) Educate IT staff on the risks and signs of exploitation to enable rapid incident response.