USN-4011-1 fixed several vulnerabilities in Jinja2. This update provides the corresponding update for Ubuntu 12.04 ESM and Ubuntu 14.04 ESM.
Original advisory details:
Olivier Dony discovered that Jinja incorrectly handled str.format. An attacker could possibly use this issue to escape the sandbox. (CVE-2016-10745)
Brian Welch discovered that Jinja incorrectly handled str.format_map. An attacker could possibly use this issue to escape the sandbox. (CVE-2019-10906)