Critical Vulnerability Information 1. Vulnerability Overview Affected Product: ToToLink A720R Router Firmware Version: V4.1.5cu.614_B20230630 (other versions need verification) Vulnerability Type: Stack Buffer Overflow Vulnerable Component: sysconf binary file, sub_401EE0 function Prerequisites: Requires control over the content of /proc/stat file or write access to the local filesystem (local exploitation only) 2. Exploitation Path 3. Vulnerable Binary File: sysconf. 4. 0-day Command Injection Exploitation Path: In the sysconf binary, at line 22, reads content from the /proc/stat file, and then at line 32, parses the string. Here, is a single-byte char, but writes at least one , leading to a buffer overflow vulnerability. 5. Proof of Concept (PoC) for Vulnerability Reproduction: