Executive brief
A security vulnerability has been identified in the Tenda CX12L router, a device used to provide wireless internet connectivity. An attacker can exploit this flaw to crash the router's management interface or potentially take full control of the device. This could lead to unauthorized monitoring of network traffic or service outages for connected users.
Technical details
A stack-based buffer overflow vulnerability exists in the Tenda CX12L router (firmware version 16.03.53.12) within the 'fromRouteStatic' function of the '/goform/RouteStatic' endpoint. The root cause is the unsafe use of the 'sprintf' function, which processes the user-controlled 'page' parameter into a fixed-size 256-byte buffer without proper bounds checking. An attacker can trigger this overflow by sending a POST request with an oversized 'page' argument. Successful exploitation can lead to memory corruption, denial of service (DoS) by crashing the web server process, or arbitrary code execution by overwriting the return address on the stack. A public proof-of-concept (PoC) has been released.
Affected products
- Tenda CX12L Router 16.03.53.12
Timeline
- 2026-03-30: disclosed: Initial disclosure on GitHub by researcher
- 2026-04-06: advisory: NVD/VulDB publication date