Executive brief
A security vulnerability has been identified in the Edimax EW-7438RPn Wi-Fi extender, a device used to increase wireless network coverage. An attacker can exploit this flaw to crash the device or potentially take full control of it by sending a specially crafted web request. This could lead to a complete loss of internet connectivity through the extender and unauthorized access to the device's settings.
Technical details
A stack-based buffer overflow exists in the 'formLicence' function within the '/goform/formLicence' component of the Edimax EW-7438RPn firmware version 1.31. The vulnerability is caused by 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 exploit this by sending an overly long string in the 'submit-url' argument, allowing them to overwrite the return address on the stack. Successful exploitation can lead 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: advisory: Initial disclosure and NVD publication
- 2026-05-25: disclosed: Public exploit code released on GitHub