ppm2tiff does not check the return value of the TIFFScanlineSize function, which allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted PPM image that triggers an integer overflow, a zero-memory allocation, and a heap-based buffer overflow.
https://exchange.xforce.ibmcloud.com/vulnerabilities/79750
http://www.ubuntu.com/usn/USN-1631-1
http://www.securityfocus.com/bid/56372
http://www.openwall.com/lists/oss-security/2012/11/02/7
http://www.openwall.com/lists/oss-security/2012/11/02/3
http://www.debian.org/security/2012/dsa-2575
http://secunia.com/advisories/51133
http://rhn.redhat.com/errata/RHSA-2012-1590.html
http://lists.opensuse.org/opensuse-updates/2013-01/msg00076.html