Certain legacy functionality in fusermount in fuse 2.8.5 and earlier, when util-linux does not support the --no-canonicalize option, allows local users to bypass intended access restrictions and unmount arbitrary directories via a symlink attack.
fuse.git.sourceforge.net/git/gitweb.cgi?p=fuse/fuse%3Ba=commit%3Bh=cbd3a2a84068aae6e3fe32939d88470d712dbf47
lists.opensuse.org/opensuse-security-announce/2011-04/msg00000.html
www.openwall.com/lists/oss-security/2011/02/02/2
www.openwall.com/lists/oss-security/2011/02/03/5
www.openwall.com/lists/oss-security/2011/02/08/4