The pstmexptmod function in MatrixSSL before 3.8.4 allows remote attackers to cause a denial of service (invalid free and crash) via a base zero value for the modular exponentiation.
The pstmreverse function in MatrixSSL before 3.8.4 allows remote attackers to cause a denial of service (invalid memory read and crash) via a (1) zero value or (2) the key's modulus for the secret key during RSA key exchange.