CVE-2020-10938-buffer overflow/out-of-bounds write in compress.c:HuffmanDecodeImage()

There is an out-of-bounds write that is likely exploitable while performing Huffman decoding of Fax images. The technical details are as follows.

 390 MagickExport MagickPassFail HuffmanDecodeImage(Image *image)
 391 {
 392 const HuffmanTable
 393 *entry;
 394
 [...]
 412
 413 long
 414 count,
 415 y;
 416
 [...]
 420 register long
 421 i,
 422 x;
 423
 [...]
 462 InitializeHashTable(mw_hash,TWTable,MWHashA,MWHashB);
 463 …