Debian Security Advisory DSA 1021-1 – Max Vozeler from the Debian Audit Project discovered that pstopnm, a converter from Postscript to the PBM, PGM and PNM formats, launches Ghostscript in an insecure manner, which might lead to the execution of arbitrary shell commands, when converting specially crafted Postscript files.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/45089/dsa-1021-1.txt
Source: https://packetstormsecurity.com/files/45089/Debian-Linux-Security-Advisory-1021-1.html