"A flaw was found in all released versions of m2crypto, where they are vulnerable to Bleichenbacher timing attacks in the RSA decryption API via the timed processing of valid PKCS#1 v1.5 Ciphertext. The highest threat from this vulnerability is to confidentiality."
The CVE references https://gitlab.com/m2crypto/m2crypto/-/issues/285 but that gets called a duplicate of a private bug. So, it's unclear if this has been fixed, but no recent commits seem relevant.
This needs to be fixed upstream in openssl, it seems: