Tenda AC8v4 Stack Overflow Vulnerability in openSchedWifi Function

A stack overflow vulnerability has been identified in the Tenda AC8v4 router, specifically in version V16.03.34.06. The issue arises in the 'setSchedWifi' function within the '/goform/openSchedWifi' file. The vulnerability allows for a stack-based buffer overflow by manipulating the 'schedStartTime' parameter in a POST request. The function does not properly validate the input, enabling the user to exceed the buffer capacity and overwrite adjacent memory.

Impact

Exploitation of this vulnerability leads to a stack-based buffer overflow, which can commonly result in arbitrary code execution or causing the device to crash.

Reproduction

The vulnerability can be reproduced by sending a POST request to '/goform/openSchedWifi' with the 'schedStartTime' parameter. The value of this parameter should be crafted to exceed 25 bytes, which will trigger the buffer overflow by overwriting the stack.