mruby through 2.1.2-rc has a heap-based buffer overflow in the mrb_yield_with_class function in vm.c because of incorrect VM stack handling. It can be triggered via the stack_copy function.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-15866
Reference (s):
- https://github.com/mruby/mruby/issues/5042