ImageMagick has Heap Buffer Over-Read in BilateralBlurImage

BilateralBlurImage contains a heap buffer over-read caused by an incorrect conversion. When processing a crafted image with the -bilateral-blur operation an out of bounds read can occur.

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==676172==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x50a0000079c0 at pc 0x57b483c722f7 bp 0x7fffc0acd380 sp 0x7fffc0acd370
READ of size 4 at 0x50a0000079c0 thread T0