The Linux umount command as provided in the util-linux package in versions 2.8 to 2.12q, 2.13-pre1 and 2.13-pre2, allows for bypass of the nosuid and nodev when a user uses the -r option.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/40000/umountFlaw.txt
Source: https://packetstormsecurity.com/files/40000/umountFlaw.txt.html