Executive brief
A security vulnerability exists in the Tenda CX12L router, a device used to provide wireless internet in homes and small offices. An attacker on the local network can exploit this flaw to crash the router's management interface or potentially take full control of the device. This could allow an attacker to monitor network traffic, steal sensitive data, or use the router as a jumping-off point to attack other devices connected to the network.
Technical details
A stack-based buffer overflow vulnerability exists in the Tenda CX12L router (firmware version 16.03.53.12) within the 'fromP2pListFilter' function of the '/goform/P2pListFilter' 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 on the local network can send a specially crafted POST request with an oversized 'page' argument to overwrite adjacent memory on the stack. Successful exploitation can lead to a Denial of Service (DoS) by crashing the web server or arbitrary code execution by overwriting the return address. A public proof-of-concept (PoC) exploit is available.
Affected products
- Tenda CX12L Router 16.03.53.12
Timeline
- 2026-03-30: disclosed: Vulnerability details and PoC shared on GitHub by researcher
- 2026-04-06: advisory: Initial disclosure via VulDB and NVD