An issue was discovered in OpenSC through 0.19.0 and 0.20.x through 0.20.0-rc3. libopensc/pkcs15-prkey.c has an incorrect free operation in sc_pkcs15_decode_prkdf_entry.
https://github.com/OpenSC/OpenSC/commit/6ce6152284c47ba9b1d4fe8ff9d2e6a3f5ee02c7