The init_copy function in kernel.c in mruby 1.4.1 makes initialize_copy calls for TT_ICLASS objects, which allows attackers to cause a denial of service (mrb_hash_keys uninitialized pointer and application crash) or possibly have unspecified other impact.
https://lists.debian.org/debian-lts-announce/2022/05/msg00006.html
https://github.com/mruby/mruby/issues/4027
https://github.com/mruby/mruby/commit/b64ce17852b180dfeea81cf458660be41a78974d