OpenSC before 0.20.0 has a double free in coolkey_free_private_data because coolkey_add_object in libopensc/card-coolkey.c lacks a uniqueness check.
https://github.com/OpenSC/OpenSC/compare/0.19.0...0.20.0
https://github.com/OpenSC/OpenSC/commit/c246f6f69a749d4f68626b40795a4f69168008f4