Null Pointer Dereference vulnerability exists in TRENDnet TEW-755AP 1.11B03 TEW-755AP2KAC 1.11B03 TEW-821DAP2KAC 1.11B03 and TEW-825DAP 1.11B03 which could let a remote malicious user cause a denial of service by sending the POST request to apply_cgi via the lang action without a language key.