A command injection vulnerability exists in the D-Link DIR-882 Router firmware DIR882A1_FW102B02 within the `prog.cgi` and `rc` binaries. The `sub_4438A4` function in `prog.cgi` stores user-supplied DDNS parameters (`ServerAddress` and `Hostname`) in NVRAM via `nvram_safe_set`. These values are later retrieved in the `start_DDNS_ipv4` function of `rc` using `nvram_safe_get` and concatenated into DDNS shell commands executed via `twsystem()` without proper sanitization. Partial string comparison is performed but is insufficient to prevent command injection. An unauthenticated remote attacker can exploit this vulnerability to execute arbitrary commands on the device through specially crafted HTTP requests to the router's web interface.