The OpenSSL Team reports:
A weakness in the OpenSSL CMS and PKCS #7 code can be exploited using Bleichenbacher's attack on PKCS #1 v1.5 RSA padding also known as the million message attack (MMA). Only users of CMS, PKCS #7, or S/MIME decryption operations are affected. A successful attack needs on average 2^20 messages. In practice only automated systems will be affected as humans will not be willing to process this many messages. SSL/TLS applications are NOT affected by this problem since the SSL/TLS code does not use the PKCS#7 or CMS decryption code.