The default configuration of su in /etc/pam.d/su in GNU coreutils 5.2.1 allows local users to gain the privileges of a (1) locked or (2) expired account by entering the account name on the command line, related to improper use of the pam_succeed_if.so module.
Race condition in Core Utilities (coreutils) 5.2.1, when (1) mkdir, (2) mknod, or (3) mkfifo is running with the -m switch, allows local users to modify permissions of other files.