Moonlight was prone to several security problems:

CVE-2011-0989: modification of read-only values via
RuntimeHelpers.InitializeArray CVE-2011-0990: buffer
overflow due to race condition in in Array.FastCopy
CVE-2011-0991: use-after-free due to DynamicMethod
resurrection CVE-2011-0992: information leak due to
improper thread finalization