CVE-2026-2181 is a stack-based buffer overflow vulnerability identified in the Tenda RX3 router firmware version 16.03.13.11. The vulnerability resides in an unknown functionality associated with the /goform/openSchedWifi file, specifically involving the schedStartTime and schedEndTime parameters. By crafting malicious input for these parameters, an attacker can overflow the stack buffer, potentially overwriting critical control data such as return addresses. This can lead to arbitrary code execution with elevated privileges on the device. The attack vector is remote network access, requiring no authentication or user interaction, making exploitation straightforward for attackers with network access to the device. The CVSS 4.0 score is 8.7 (high), reflecting the ease of exploitation and the severe impact on confidentiality, integrity, and availability. Although no active exploitation has been reported, the public release of exploit code significantly raises the threat level. The vulnerability affects only the specified firmware version, and no patches have been linked yet, indicating that affected users must monitor vendor advisories closely. The flaw could be leveraged to compromise home or small office networks relying on Tenda RX3 routers, enabling attackers to intercept traffic, disrupt network services, or pivot into internal networks.

For European organizations, this vulnerability poses a significant risk to network security, particularly for small and medium enterprises or home offices using Tenda RX3 routers. Successful exploitation could lead to unauthorized access to internal networks, interception of sensitive data, disruption of network availability, and potential lateral movement to other systems. Given the router’s role as a network gateway, compromise could undermine the confidentiality and integrity of organizational communications. The lack of authentication and user interaction requirements lowers the barrier for attackers, increasing the likelihood of exploitation. This could result in data breaches, operational downtime, and reputational damage. Additionally, critical infrastructure or government entities using these devices may face heightened risks due to the strategic importance of their networks. The public availability of exploit code further elevates the threat, necessitating urgent mitigation to prevent widespread attacks.

1. Immediately restrict external network access to the Tenda RX3 router’s management interfaces, especially the /goform/openSchedWifi endpoint, using firewall rules or network segmentation. 2. Monitor network traffic for unusual requests targeting the schedStartTime and schedEndTime parameters to detect potential exploitation attempts. 3. Apply firmware updates from Tenda as soon as a patch addressing CVE-2026-2181 is released; regularly check vendor advisories. 4. If patching is delayed, consider replacing vulnerable devices with alternative routers from vendors with timely security support. 5. Implement network intrusion detection/prevention systems (IDS/IPS) with signatures targeting this vulnerability or related exploit patterns. 6. Educate IT staff about the vulnerability and ensure incident response plans include steps for handling potential exploitation. 7. Limit administrative access to the router to trusted internal networks and use strong authentication mechanisms where possible. 8. Conduct regular security audits of network devices to identify and remediate outdated firmware versions.