There are 2 open security issues in buster.
1 important issue:
OpenDMARC through 1.3.2 and 1.4.x allows attacks that inject authentication results to provide false information about the domain that originated an e-mail message. This is caused by incorrect parsing and interpretation of SPF/DKIM authentication results, as demonstrated by the example.net(.example.com substring.
1 issue left for the package maintainer to handle:
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.
You can find information about how to handle this issue in the security team's documentation.