USN-3216-1 introduced a regression in Firefox.
USN-3216-1 fixed vulnerabilities in Firefox. The update resulted in a startup crash when Firefox is used with XRDP. This update fixes the problem.
30 March 2017
A security issue affects these releases of Ubuntu and its derivatives:
USN-3216-1 introduced a regression in Firefox.
USN-3216-1 fixed vulnerabilities in Firefox. The update resulted in a startup crash when Firefox is used with XRDP. This update fixes the problem.
We apologize for the inconvenience.
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 bypass same origin restrictions, obtain sensitive information, spoof the addressbar, spoof the print dialog, cause a denial of service via application crash or hang, or execute arbitrary code. (CVE-2017-5398, CVE-2017-5399, CVE-2017-5400, CVE-2017-5401, CVE-2017-5402, CVE-2017-5403, CVE-2017-5404, CVE-2017-5405, CVE-2017-5406, CVE-2017-5407, CVE-2017-5408, CVE-2017-5410, CVE-2017-5412, CVE-2017-5413, CVE-2017-5414, CVE-2017-5415, CVE-2017-5416, CVE-2017-5417, CVE-2017-5418, CVE-2017-5419, CVE-2017-5420, CVE-2017-5421, CVE-2017-5422, CVE-2017-5426, CVE-2017-5427)
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to restart Firefox to make all the necessary changes.