Document:
[CVE-2020-1931] Apache SpamAssassin Nefarious rule configuration
(.cf) files can be configured to run system commands with warnings
Security: CVE-2020-1931
Security: https://svn.apache.org/repos/asf/spamassassin/branches/3.4/\
build/announcements/3.4.4.txt
Security: https://cve.mitre.org/cgi-bin/cvename.cgi?name=2020-1931