The rtl8192cd Wi-Fi kernel driver in the Realtek rtl819x Jungle SDK (all known versions through v3.4.14B) does not perform any access control checks on the write_mem (ioctl 0x89F5) and read_mem (ioctl 0x89F6) debug handlers, which are compiled into production builds via the unconditionally defined IOCTL_DEBUG_CMD macro in 8192cd_cfg.h