In versions of mruby up to and including 1.4.0, a use-after-free vulnerability exists in src/io.c::File#initilializecopy(). An attacker that can cause Ruby code to be run can possibly use this to execute arbitrary code.

In versions of mruby up to and including 1.4.0, an integer overflow exists in src/vm.c::mrbvmexec() when handling OPGETUPVAR in the presence of deep scope nesting, resulting in a use-after-free. An attacker that can cause Ruby code to be run can use this to possibly execute arbitrary code.