Executive brief
TOTOLINK A800R is a residential WiFi router that manages wireless network configuration. A remotely exploitable stack-based buffer overflow in the WPS (WiFi Protected Setup) configuration function allows attackers to crash the device or potentially execute code, disrupting network connectivity for all users.
Technical details
A stack-based buffer overflow vulnerability exists in the setWiFiWpsConfig function within the wps.so component of TOTOLINK A800R. The vulnerability is triggered by improper validation of the "pin" parameter, which is passed directly to strncpy without length checking. The attack is remotely exploitable via HTTP POST requests to /cgi-bin/cstecgi.cgi and requires no authentication. An attacker can overflow the stack buffer with oversized input to achieve denial of service or code execution. Public exploits have been released and the vulnerability affects firmware version 4.1.2cu.5137_B20200730 and likely other versions.
Affected products
- TOTOLINK A800R 4.1.2cu.5137_B20200730
Timeline
- 2026-08-14: disclosed
- exploited: Public exploit available