USN-5787-2: Libksba vulnerability

USN-5787-1 fixed vulnerabilities in Libksba. This update provides the
corresponding updates for Ubuntu 16.04 ESM and Ubuntu 14.04 ESM.

Original advisory details:

It was discovered that Libksba incorrectly handled parsing CRL signatures.
A remote attacker could use this issue to cause Libksba to crash, resulting
in a denial of service, or possibly execute arbitrary code.

advisory code crash crl denial of service issue parsing service signatures ubuntu update updates usn vulnerabilities vulnerability