Updated libpng12 package fixes security vulnerabilities:

The png_do_expand_palette function in libpng before 1.6.8 allows remote
attackers to cause a denial of service (NULL pointer dereference and
application crash) via a PLTE chunk of zero bytes or a NULL palette,
related to pngrtran.c and pngset.c (CVE-2013-6954).

An integer overflow leading to a heap-based buffer overflow was found
in the png_set_sPLT() and png_set_text_2() API functions of libpng. An
attacker could create a specially-crafted image file and render it
with an application written to explicitly call png_set_sPLT() or
png_set_text_2() function, could cause libpng to crash or execute
arbitrary code with the permissions of the user running such an
application (CVE-2013-7353).

An integer overflow leading to a heap-based buffer overflow was found
in the png_set_unknown_chunks() API function of libpng. An attacker
could create a specially-crafted image file and render it with an
application written to explicitly call png_set_unknown_chunks()
function, could cause libpng to crash or execute arbitrary code
with the permissions of the user running such an application
(CVE-2013-7354).