spice: Off-by-one error in array access in spice/server/memslot.c

Spice, versions 0.5.2 through 0.14.1, are vulnerable to an out-of-bounds read due to an off-by-one error in memslotgetvirt. This may lead to a denial of service, or, in the worst case, code-execution by unauthenticated attackers...