A local stack-based buffer overflow vulnerability exists in the infostat.cgi and cstecgi.cgi binaries of ToToLink routers (A720R V4.1.5cu.614_B20230630, LR1200GB V9.1.0u.6619_B20230130, and NR1800X V9.1.0u.6681_B20230703). Both programs parse the contents of /proc/net/arp using sscanf() with "%s" format specifiers into fixed-size stack buffers without length validation. Specifically, one function writes user-controlled data into a single-byte buffer, and the other into adjacent small arrays without bounds checking. An attacker who controls the contents of /proc/net/arp can trigger memory corruption, leading to denial of service or potential arbitrary code execution.
| Software | From | Fixed in |
|---|---|---|
| totolink / a720r_firmware | 4.1.5cu.614_b20230630 | 4.1.5cu.614_b20230630.x |
| totolink / lr1200gb_firmware | 9.1.0u.6619_b20230130 | 9.1.0u.6619_b20230130.x |
| totolink / nr1800x_firmware | 9.1.0u.6681_b20230703 | 9.1.0u.6681_b20230703.x |