There is 1 open security issue in buster.
1 issue left for the package maintainer to handle:
Nagios 4.4.5 allows an attacker, who already has administrative access to change the "URL for JSON CGIs" configuration setting, to modify the Alert Histogram and Trends code via crafted versions of the archivejson.cgi, objectjson.cgi, and statusjson.cgi files. NOTE: this vulnerability has been mistakenly associated with CVE-2020-1408.
You can find information about how to handle this issue in the security team's documentation.