The sPLT chunk handling code (png_set_sPLT function in pngset.c) in libpng 1.0.6 through 1.2.12 uses a sizeof operator on the wrong data type, which allows context-dependent attackers to cause a denial of service (crash) via malformed sPLT chunks that trigger an out-of-bounds read.

Buffer overflow in the png_decompress_chunk function in pngrutil.c in libpng before 1.2.12 allows context-dependent attackers to cause a denial of service and possibly execute arbitrary code via unspecified vectors related to "chunk error processing," possibly involving the "chunk_name".