In NetHack before 3.6.6, some out-of-bound values for the hilite_status option can be exploited. NetHack 3.6.6 resolves this issue.
{ "binaries": [ { "binary_name": "nethack-common", "binary_version": "3.6.1-1" }, { "binary_name": "nethack-console", "binary_version": "3.6.1-1" }, { "binary_name": "nethack-lisp", "binary_version": "3.6.1-1" }, { "binary_name": "nethack-x11", "binary_version": "3.6.1-1" } ] }