Incomplete blacklist vulnerability in nrpc.c in Nagios Remote Plug-In Executor (NRPE) before 2.14 might allow remote attackers to execute arbitrary shell commands via "$()" shell metacharacters, which are processed by bash.
https://bugzilla.novell.com/show_bug.cgi?id=807241
http://www.occamsec.com/vulnerabilities.html#nagios_metacharacter_vulnerability
http://www.exploit-db.com/exploits/24955
http://seclists.org/bugtraq/2013/Feb/119
http://lists.opensuse.org/opensuse-security-announce/2013-04/msg00006.html
http://lists.opensuse.org/opensuse-security-announce/2013-04/msg00005.html