Executive brief
A security vulnerability exists in the Edimax EW-7438RPn Wi-Fi extender. This device is used to expand wireless network coverage in homes and small offices. An attacker can exploit this flaw to crash the device or potentially take full control of it, leading to a complete loss of internet connectivity and potential 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 flaw is located within the 'formSDHCP' function in the '/goform/formSDHCP' endpoint. The root cause is a lack of bounds checking on the 'submit-url' POST parameter, which is copied directly into a local stack variable. A remote attacker with low privileges (authenticated) can provide an oversized string to overwrite the return address on the stack, leading to arbitrary code execution or a persistent denial of service (device crash). As of the advisory date, the vendor has not responded to disclosure attempts.
Affected products
- Edimax EW-7438RPn 1.31
Timeline
- 2026-05-25: disclosed: Exploit disclosed to the public
- 2026-05-25: advisory