xymond in Xymon 4.1.x, 4.2.x, and 4.3.x before 4.3.25 allow remote authenticated users to execute arbitrary commands via shell metacharacters in the adduser_name argument in (1) web/useradm.c or (2) web/chpasswd.c.
https://sourceforge.net/p/xymon/code/7892/
http://www.securityfocus.com/archive/1/537522/100/0/threaded
http://www.debian.org/security/2016/dsa-3495
http://packetstormsecurity.com/files/153620/Xymon-useradm-Command-Execution.html