libpng: memory corruption flaw

The pngsettext2 function in pngset.c in libpng 1.0.x before 1.0.59, 1.2.x before 1.2.49, 1.4.x before 1.4.11, and 1.5.x before 1.5.10 allows remote attackers to cause a denial of service crash or execute arbitrary code via a crafted text chunk in a PNG image file, which triggers a memory allocati...