MatrixSSL before 3.8.7, when the DHE_RSA based cipher suite is supported, makes it easier for remote attackers to obtain RSA private key information by conducting a Lenstra side-channel attack.
https://people.redhat.com/~fweimer/rsa-crt-leaks.pdf
https://github.com/matrixssl/matrixssl/blob/master/CHANGES.md#validation-of-rsa-signature-creation
https://access.redhat.com/blogs/766093/posts/1976703