Integer overflow in the png_set_unknown_chunks function in libpng/pngset.c in libpng before 1.5.14beta08 allows context-dependent attackers to cause a denial of service (segmentation fault and crash) via a crafted image, which triggers a heap-based buffer overflow.
http://www.securityfocus.com/bid/67345
http://sourceforge.net/p/libpng/bugs/199/
http://seclists.org/oss-sec/2014/q2/83
http://lists.opensuse.org/opensuse-updates/2014-05/msg00015.html