In the OpenSSL address implementation the hard coded 1024 bit DH p parameter was not prime. The effective cryptographic strength of a key exchange using these parameters was weaker than the one one could get by using a prime p. The existence of a trapdoor that makes possible for an eavesdropper to recover the shared secret cannot be ruled out. A new prime modulus p parameter has been generated by Socat developer using OpenSSL dhparam command. In addition the new parameter is 2048 bit long. Affected versions can be downloaded from:http://www.dest-unreach.org/socat/download/Socat-1.7.3.0-b8:”]
Source: http://www.dest-unreach.org/socat/contrib/socat-secadv7.html