Executive brief
A security vulnerability exists in the Edimax EW-7438RPn Wi-Fi extender, a device used to increase wireless network coverage. An attacker can send a specially crafted web request to the device to cause it to crash or potentially take full control of the hardware. This could lead to a total loss of internet connectivity through the extender and allow unauthorized access to the local network.
Technical details
A stack-based buffer overflow vulnerability exists in the 'webs' binary of the Edimax EW-7438RPn firmware version 1.31. The vulnerability is located in the 'formrefresh' function within the '/goform/formrefresh' endpoint. The 'submit-url' POST parameter is copied into a local stack buffer without adequate bounds checking, allowing an attacker to overwrite the function's return address. Exploitation requires network reachability and basic authentication (PR:L). Successful exploitation can lead to remote code execution (RCE) or a persistent denial of service (DoS) by crashing the device's web server. As of the advisory date, the vendor has not responded to disclosure attempts.
Affected products
- Edimax EW-7438RPn 1.31
Timeline
- 2026-05-25: advisory: Vulnerability disclosed via VulDB and NVD
- 2026-05-25: disclosed: Public PoC released on GitHub