USN-3801-1 caused some minor regressions in Firefox.
USN-3801-1 fixed vulnerabilities in Firefox. The update introduced various minor regressions. This update fixes the problems.
23 November 2018
A security issue affects these releases of Ubuntu and its derivatives:
USN-3801-1 caused some minor regressions in Firefox.
USN-3801-1 fixed vulnerabilities in Firefox. The update introduced various minor regressions. This update fixes the problems.
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 cause a denial of service, bypass CSP restrictions, spoof the protocol registration notification bar, leak SameSite cookies, bypass mixed content warnings, or execute arbitrary code. (CVE-2018-12388, CVE-2018-12390, CVE-2018-12392, CVE-2018-12393, CVE-2018-12398, CVE-2018-12399, CVE-2018-12401, CVE-2018-12402, CVE-2018-12403)
Multiple security issues were discovered with WebExtensions in Firefox. If a user were tricked in to installing a specially crafted extension, an attacker could potentially exploit these to bypass domain restrictions, gain additional privileges, or run content scripts in local pages without permission. (CVE-2018-12395, CVE-2018-12396, CVE-2018-12397)
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.
Vulmon