USN-3991-1 caused a regression in Firefox.
USN-3991-1 fixed vulnerabilities in Firefox. The update caused a regression which resulted in issues when upgrading between Ubuntu releases. This update fixes the problem.
6 June 2019
A security issue affects these releases of Ubuntu and its derivatives:
USN-3991-1 caused a regression in Firefox.
USN-3991-1 fixed vulnerabilities in Firefox. The update caused a regression which resulted in issues when upgrading between Ubuntu releases. 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 cause a denial of service, spoof the browser UI, trick the user in to launching local executable binaries, obtain sensitive information, conduct cross-site scripting (XSS) attacks, or execute arbitrary code. (CVE-2019-11691, CVE-2019-11692, CVE-2019-11693, CVE-2019-11695, CVE-2019-11696, CVE-2019-11699, CVE-2019-11701, CVE-2019-7317, CVE-2019-9800, CVE-2019-9814, CVE-2019-9817, CVE-2019-9819, CVE-2019-9820, CVE-2019-9821)
It was discovered that pressing certain key combinations could bypass addon installation prompt delays. If a user opened a specially crafted website, an attacker could potentially exploit this to trick them in to installing a malicious extension. (CVE-2019-11697)
It was discovered that history data could be exposed via drag and drop of hyperlinks to and from bookmarks. If a user were tricked in to dragging a specially crafted hyperlink to the bookmark toolbar or sidebar, and subsequently back in to the web content area, an attacker could potentially exploit this to obtain sensitive information. (CVE-2019-11698)
A type confusion bug was discovered with object groups and UnboxedObjects. If a user were tricked in to opening a specially crafted website after enabling the UnboxedObjects feature, an attacker could potentially exploit this to bypass security checks. (CVE-2019-9816)
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