USN-3611-1 fixed a vulnerability in OpenSSL. This update provides the corresponding update for Ubuntu 12.04 ESM.
Original advisory details:
It was discovered that OpenSSL incorrectly parsed the IPAddressFamily extension in X.509 certificates, resulting in an erroneous display of the certificate in text format. (CVE-2017-3735)
It was discovered that OpenSSL incorrectly handled certain ASN.1 types. A remote attacker could possibly use this issue to cause a denial of service. (CVE-2018-0739)