CVE-2025-11524 is a stack-based buffer overflow vulnerability identified in the Tenda AC7 router firmware version 15.03.06.44. The vulnerability arises from improper processing of the ddnsEn parameter in the /goform/SetDDNSCfg endpoint, which is part of the router's Dynamic DNS configuration interface. By sending a specially crafted request manipulating this argument, an attacker can overflow the stack buffer, potentially overwriting the return address or other control data on the stack. This can lead to arbitrary code execution with the privileges of the router's firmware process, which typically runs with high system privileges. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, making it accessible to any attacker who can reach the device's management interface. The CVSS v4.0 base score is 8.7, reflecting the high impact on confidentiality, integrity, and availability, combined with low attack complexity and no required privileges or user interaction. Although no active exploitation has been reported, a public exploit is available, increasing the likelihood of attacks. The lack of an official patch at the time of disclosure further elevates the risk. This vulnerability affects network infrastructure devices widely used in home and small office environments, potentially allowing attackers to gain persistent control over affected routers, intercept or manipulate network traffic, and pivot to internal networks.

The impact of CVE-2025-11524 is significant for organizations relying on Tenda AC7 routers, especially in environments where these devices serve as primary gateways or manage critical network functions. Exploitation can lead to full compromise of the router, enabling attackers to execute arbitrary code, disrupt network availability, intercept or alter network traffic, and potentially launch further attacks against internal systems. This undermines the confidentiality, integrity, and availability of organizational networks. The remote, unauthenticated nature of the exploit increases the risk of widespread attacks, including automated scanning and exploitation campaigns. Small and medium businesses, home offices, and even some enterprise environments using these routers are vulnerable. The absence of a patch at disclosure time means organizations must rely on mitigations to reduce exposure. Given the router's role in network perimeter defense, successful exploitation could facilitate lateral movement and data exfiltration, posing a severe threat to organizational security.

1. Immediately restrict access to the router's management interfaces, especially the /goform/SetDDNSCfg endpoint, by limiting exposure to trusted internal networks only. 2. Implement network segmentation to isolate vulnerable routers from critical infrastructure and sensitive data environments. 3. Monitor network traffic for unusual or malformed requests targeting the DDNS configuration endpoint, using IDS/IPS solutions with custom signatures if necessary. 4. Disable Dynamic DNS features if not required to reduce the attack surface. 5. Regularly check for firmware updates from Tenda and apply patches as soon as they become available. 6. If patching is not immediately possible, consider replacing affected devices with alternative hardware from vendors with timely security support. 7. Employ strong network perimeter defenses, including firewalls and VPNs, to limit remote access to router management interfaces. 8. Educate network administrators about this vulnerability and encourage proactive security hygiene, including changing default credentials and auditing device configurations.