Rocks Clusters 4.1 and earlier allows local users to gain privileges via commands enclosed with escaped backticks (\`) in an argument to the (1) mount-loop (mount-loop.c) or (2) umount-loop (umount-loop.c) command, which is not filtered in a system function call.
https://exchange.xforce.ibmcloud.com/vulnerabilities/27758
http://xavier.tigerteam.se/advisories/TSEAD-200606-6.txt
http://www.vupen.com/english/advisories/2006/2833
http://www.securityfocus.com/archive/1/440126/100/0/threaded