A stack buffer overflow vulnerability exists in the ToToLink A720R Router firmware version 4.1.5cu.614_B20230630 within the sysconf binary. The vulnerability arises from improper handling of the /proc/stat file content, where a single-byte variable is used with the %s format specifier in sscanf(), allowing crafted input to overwrite adjacent stack memory. This flaw could enable an attacker with filesystem write privileges to execute arbitrary code on the device.