OpenDMARC through 1.3.2 and 1.4.x through 1.4.0-Beta1 has improper null termination in the function opendmarc_xml_parse that can result in a one-byte heap overflow in opendmarc_xml when parsing a specially crafted DMARC aggregate report. This can cause remote memory corruption when a '\0' byte overwrites the heap metadata of the next chunk and its PREV_INUSE flag.