CVE-2025-11586 is a stack-based buffer overflow vulnerability identified in the Tenda AC7 router firmware version 15.03.06.44. The flaw exists in an unspecified function within the /goform/setNotUpgrade endpoint, where the 'newVersion' parameter is improperly validated, allowing an attacker to overflow the stack buffer. This vulnerability can be exploited remotely without requiring authentication or user interaction, making it highly accessible to attackers. Successful exploitation could enable arbitrary code execution on the device, potentially leading to full compromise of the router. This could allow attackers to intercept, modify, or disrupt network traffic, launch further attacks within the network, or create persistent backdoors. 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) reflects network attack vector, low complexity, no authentication, no user interaction, and high impact on confidentiality, integrity, and availability. Although no known exploits are currently active in the wild, the public disclosure of the exploit code increases the likelihood of imminent attacks. The vulnerability affects a widely deployed consumer router model, which is often used in small and medium enterprise environments as well as home offices, increasing the potential attack surface.

For European organizations, exploitation of this vulnerability could lead to severe consequences including unauthorized access to internal networks, interception of sensitive communications, and disruption of business operations. Compromise of routers can facilitate lateral movement by attackers, enabling them to bypass perimeter defenses and access critical systems. This is particularly concerning for sectors reliant on secure and stable network infrastructure such as finance, healthcare, and government. The ability to execute arbitrary code remotely without authentication significantly raises the risk profile, as attackers can deploy malware, exfiltrate data, or disrupt services at scale. Additionally, the widespread use of Tenda AC7 devices in Europe, especially in small and medium-sized enterprises and home office environments, increases the likelihood of exploitation. The lack of current patches or mitigations from the vendor further exacerbates the risk, potentially leading to increased incident response costs and reputational damage.

Organizations should immediately inventory their network to identify any Tenda AC7 devices running firmware version 15.03.06.44. Until an official patch is released, network administrators should restrict access to the router management interface by implementing IP whitelisting and disabling remote management features. Deploy network segmentation to isolate vulnerable devices from critical infrastructure and sensitive data. Employ intrusion detection and prevention systems (IDS/IPS) to monitor for anomalous traffic patterns indicative of exploitation attempts targeting /goform/setNotUpgrade. Regularly update router firmware as soon as vendor patches become available, and verify the integrity of firmware updates through cryptographic signatures if supported. Additionally, consider replacing vulnerable devices with models from vendors with stronger security track records if patching is delayed. Educate users about the risks of exposing router management interfaces to the internet and enforce strong network access controls. Finally, maintain up-to-date backups and incident response plans tailored to network device compromise scenarios.