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 unspecified functionality accessed via the /goform/openSchedWifi endpoint. Specifically, improper handling and validation of the schedStartTime and schedEndTime parameters allow an attacker to overflow a stack buffer. This overflow can corrupt adjacent memory, potentially enabling arbitrary code execution or denial of service. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, making it highly accessible to attackers. The CVSS 4.0 base score is 8.7, reflecting high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges or user interaction needed. Although no confirmed exploits in the wild have been reported, public exploit code is available, increasing the likelihood of attacks. The vulnerability affects a widely used consumer and small business router model, which may be deployed in home, enterprise, and critical infrastructure environments. The lack of an official patch or mitigation guidance from the vendor increases the urgency for organizations to implement compensating controls.

Successful exploitation of CVE-2026-2181 can lead to full compromise of affected Tenda RX3 routers. Attackers may execute arbitrary code with elevated privileges, allowing them to manipulate network traffic, intercept sensitive data, or pivot to internal networks. This threatens the confidentiality and integrity of communications passing through the device. Additionally, attackers could disrupt network availability by causing crashes or persistent denial of service. Given the router’s role as a network gateway, compromise can facilitate broader attacks on connected systems and infrastructure. The remote, unauthenticated nature of the exploit significantly increases the attack surface and risk. Organizations relying on these routers for critical connectivity or security functions face heightened exposure to espionage, data breaches, and operational disruption.

1. Immediately identify and inventory all Tenda RX3 routers running firmware version 16.03.13.11 within the network. 2. Monitor vendor channels for official firmware updates or patches addressing CVE-2026-2181 and apply them promptly once available. 3. Until patches are released, restrict remote access to the router’s management interfaces, especially the /goform/openSchedWifi endpoint, using firewall rules or network segmentation. 4. Disable or limit remote management features if not required. 5. Employ network intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics to detect exploitation attempts targeting this vulnerability. 6. Regularly audit router configurations and logs for suspicious activity related to schedStartTime or schedEndTime parameters. 7. Consider replacing vulnerable devices with models from vendors with active security support if timely patching is not feasible. 8. Educate network administrators about this vulnerability and ensure incident response plans include steps for router compromise scenarios.