Exim before 4.92.2 allows remote attackers to execute arbitrary code as root via a trailing backslash.
https://www.tenable.com/blog/how-covid-19-response-is-expanding-the-cyberattack-surface
https://www.openwall.com/lists/oss-security/2019/09/06/1
https://www.kb.cert.org/vuls/id/672565
https://www.debian.org/security/2019/dsa-4517
https://usn.ubuntu.com/4124-2/
https://usn.ubuntu.com/4124-1/
https://security.gentoo.org/glsa/201909-06
https://seclists.org/bugtraq/2019/Sep/13
https://lists.debian.org/debian-lts-announce/2019/09/msg00004.html
https://exim.org/static/doc/security/CVE-2019-15846.txt
http://www.openwall.com/lists/oss-security/2019/09/09/1
http://www.openwall.com/lists/oss-security/2019/09/08/1
http://www.openwall.com/lists/oss-security/2019/09/07/2
http://www.openwall.com/lists/oss-security/2019/09/07/1
http://www.openwall.com/lists/oss-security/2019/09/06/8
http://www.openwall.com/lists/oss-security/2019/09/06/6
http://www.openwall.com/lists/oss-security/2019/09/06/5
http://www.openwall.com/lists/oss-security/2019/09/06/4
http://www.openwall.com/lists/oss-security/2019/09/06/2
http://lists.opensuse.org/opensuse-security-announce/2019-09/msg00024.html