x2gocleansessions in X2Go Server before 4.0.0.8 and 4.0.1.x before 4.0.1.10 allows remote authenticated users to gain privileges via unspecified vectors, possibly related to backticks.
http://www.securityfocus.com/bid/65001
http://www.openwall.com/lists/oss-security/2014/05/19/4
http://www.openwall.com/lists/oss-security/2014/05/18/1
http://security.gentoo.org/glsa/glsa-201405-26.xml
http://permalink.gmane.org/gmane.linux.terminal-server.x2go.announce/83