ImageMagick: Heap overflow in pcd decoder leads to out of bounds read.

ImageMagick is free and open-source software used for editing and manipulating digital images. Prior to versions 7.1.2-15 and 6.9.13-40, ImageMagick lacks proper boundary checking when processing Huffman-coded data from PCD (Photo CD) files. The decoder contains an function that has an incorrect initialization that could cause an out of bounds read. Versions 7.1.2-15 and 6.9.13-40 contain a patch.