GNU Parallel before 20150422, when using (1) --pipe, (2) --tmux, (3) --cat, (4) --fifo, or (5) --compress, allows local users to write to arbitrary files via a symlink attack on a temporary file.
Improper Link Resolution Before File Access 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.