Buffer overflow in the pngdecompresschunk 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 "chunkname".

Heap-based buffer overflow in the alpha strip capability in libpng 1.2.7 allows context-dependent attackers to cause a denial of service (crash) when the pngdostripfiller function is used to strip alpha channels out of the image.

The sPLT chunk handling code (pngsetsPLT 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.