source: https://www.securityfocus.com/bid/41801/info

gif2png is prone to a remote buffer-overflow vulnerability because it fails to perform adequate boundary checks on user-supplied input.

Successfully exploiting this issue may allow remote attackers to execute arbitrary code in the context of the application. Failed exploit attempts will cause denial-of-service conditions.

gif2png 2.5.2 is vulnerable; other versions may also be affected. 

$> ./gif2png $(perl -e 'print "A" x 1053')