plaiter in Plait before 1.6 allows local users to overwrite arbitrary files via a symlink attack on (1) cut.$$, (2) head.$$, (3) awk.$$, and (4) ps.$$ temporary files in /tmp/.
The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.