CVE-2020-1946
In Apache SpamAssassin before 3.4.5, malicious rule configuration (.cf) files can be configured to run system commands without any output or errors. With this, exploits can be injected in a number of scenarios. In addition to upgrading to SA version 3.4.5, users should only use update channels or 3rd party .cf files from trusted places.
Source: CVE-2020-1946