USN-4216-1 fixed vulnerabilities in Firefox. This update provides the corresponding update for Ubuntu 16.04 LTS.
Original advisory details:
Multiple security issues were discovered in Firefox. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit these to cause a denial of service, obtain sensitive information, or execute arbitrary code.
71.0+build5-0ubuntu0.16.04.1