libuser / userhelper security vulnerabilities

Unsafe files handling, insufficient characters filtering...

Authentication flaw

The 1 config.guess, 2 contrib/groffer/perl/groffer.pl, and 3 contrib/groffer/perl/roff2.pl scripts in GNU troff aka groff 1.21 and earlier use an insufficient number of X characters in the template argument to the tempfile function, which makes it easier for local users to overwrite arbitrary fil...