Multiple shell programs on various Unix systems, including (1) tcsh, (2) csh, (3) sh, and (4) bash, follow symlinks when processing << redirects (aka here-documents or in-here documents), which allows local users to overwrite files of other users via a symlink attack.
Buffer overflow in ypserv in Mandrake Linux 7.1 and earlier, and possibly other Linux operating systems, allows an attacker to gain root privileges when ypserv is built without a vsyslog() function.