libpng 1.0.6 through 1.0.32, 1.2.0 through 1.2.26, and 1.4.0beta01 through 1.4.0beta19 allows context-dependent attackers to cause a denial of service (crash) and possibly execute arbitrary code via a PNG file with zero length "unknown" chunks, which trigger an access of uninitialized memory.

Memory leak in pngwutil.c in libpng 1.2.13beta1, and other versions before 1.2.15beta3, allows context-dependent attackers to cause a denial of service (memory leak or segmentation fault) via a JPEG image containing an iCCP chunk with a negative embedded profile length.