broken bytecode objects can easily crash the interpreter this is not going to be fixed it is generally agreed that there is no point in writing a bytecode verifier and putting it in cpython just for this moreover a verifier is bound to accept only a subset of all safe bytecodes so it could lead to unnecessary breakage for security purposes restricted interpreters are not going to let the user build or load random bytecodes anyway otherwise this is a won t fix case
import types

co = types.CodeType(0, 0, 0, 0, 0, 0, b'\x04\x00\x71\x00',
                    (), (), (), '', '', 1, b'')
exec(co)