Multiple vulnerabilities are found in the OpenSSL library which may generate unsafe primes for use in the Diffie-Hellman protocol that may lead to disclosure of enough information for an attacker to recover the private encryption key. Moreover, a malicious client could negotiate SSLv2 ciphers that have been disabled on the server.
Successful exploitation could lead to information disclosure.
Related vulnerabilities are fixed in OpenSSL 1.0.1r and 1.0.2f. Users with systems such as HTTPS protected websites or SSL-VPN gateways using OpenSSL to encrypt network traffic should check with their product vendors if the vulnerable OpenSSL versions are used and if so, upgrade to the fixed versions or follow the recommendations provided by the product vendors to mitigate the risk.
https://www.openssl.org/news/secadv/20160128.txt
https://www.us-cert.gov/ncas/current-activity/2016/01/28/OpenSSL-Releases-Security-Advisory
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-3197
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-0701