diff --git a/epan/packet.c b/epan/packet.c

index 1ad0320..179011e 100644

--- a/epan/packet.c

+++ b/epan/packet.c

@@ -1266,6 +1266,7 @@ dissector_get_string_handle(dissector_table_t sub_dissectors,

 {

 	dtbl_entry_t *dtbl_entry;

+	if (!string) return 0;

 	dtbl_entry = find_string_dtbl_entry(sub_dissectors, string);

 	if (dtbl_entry != NULL)

 		return dtbl_entry->current;