umount in util-linux 2.8 to 2.12q, 2.13-pre1, and 2.13-pre2, and other packages such as loop-aes-utils, allows local users with unmount permissions to gain privileges via the -r (remount) option, which causes the file system to be remounted with just the read-only flag, which effectively clears the nosuid, nodev, and other flags.
A patch for mcookie in the util-linux package for Mandrake Linux 8.2 and 9.0 uses /dev/urandom instead of /dev/random, which causes mcookie to use an entropy source that is more predictable than expected, which may make it easier for certain types of attacks to succeed.