The call to EVP_VerifyFinal() internally finalizes a copy of the digest context. This means that calls to EVP_VerifyUpdate() and EVP_VerifyFinal() can be called later to digest and verify additional data.
Since only a copy of the digest context is ever finalized the context must be cleaned up after use by calling EVP_MD_CTX_cleanup() or a memory leak will occur.
ext/openssl/ossl_pkey.c (ossl_pkey_verify): as EVP_VerifyFinal()
finalizes only a copy of the digest context, the context must be
cleaned up after initialization by EVP_MD_CTX_cleanup() or a
memory leak will occur. [ruby-core:62038] [Bug #9743]