Use-after-free vulnerability in opngreduc.c in OptiPNG Hg and 0.7.x before 0.7.3 might allow remote attackers to execute arbitrary code via unspecified vectors related to "palette reduction."
Gentoo Linux Security Advisory 201404-3 - A use-after-free error in OptiPNG could result in execution of arbitrary code or Denial of Service. Versions less than 0.7.3 are affected.