USN-5488-1 fixed vulnerabilities in OpenSSL. This update provides the corresponding updates for Ubuntu 16.04 ESM.
Original advisory details:
Chancen and Daniel Fiala discovered that OpenSSL incorrectly handled the c_rehash script. A local attacker could possibly use this issue to execute arbitrary commands when c_rehash is run.
1.0.2g-1ubuntu4.20+esm5