FreeBSD Security Advisory – A malicious client can negotiate SSLv2 ciphers that have been disabled on the server and complete SSLv2 handshakes even if all SSLv2 ciphers have been disabled, provided that the SSLv2 protocol was not also disabled via SSL_OP_NO_SSLv2. An active MITM attacker may be able to force a protocol downgrade to SSLv2, which is a flawed protocol and intercept the communication between client and server.