USN-3596-1 caused a regression in Firefox.
USN-3596-1 fixed vulnerabilities in Firefox. The update caused an issue where it was not possible to customize the toolbars when running Firefox in Unity. This update fixes the problem.
6 April 2018
A security issue affects these releases of Ubuntu and its derivatives:
USN-3596-1 caused a regression in Firefox.
USN-3596-1 fixed vulnerabilities in Firefox. The update caused an issue where it was not possible to customize the toolbars when running Firefox in Unity. 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 via application crash or opening new tabs, escape the sandbox, bypass same-origin restrictions, obtain sensitive information, confuse the user with misleading permission requests, or execute arbitrary code. (CVE-2018-5125, CVE-2018-5126, CVE-2018-5127, CVE-2018-5128, CVE-2018-5129, CVE-2018-5130, CVE-2018-5136, CVE-2018-5137, CVE-2018-5140, CVE-2018-5141, CVE-2018-5142)
It was discovered that the fetch() API could incorrectly return cached copies of no-store/no-cache resources in some circumstances. A local attacker could potentially exploit this to obtain sensitive information in environments where multiple users share a common profile. (CVE-2018-5131)
Multiple security issues were discovered with WebExtensions. If a user were tricked in to installing a specially crafted extension, an attacker could potentially exploit these to obtain sensitive information or bypass security restrictions. (CVE-2018-5132, CVE-2018-5134, CVE-2018-5135)
It was discovered that the value of app.support.baseURL is not sanitized properly. If a malicious local application were to set this to a specially crafted value, an attacker could potentially exploit this to execute arbitrary code. (CVE-2018-5133)
It was discovered that javascript: URLs with embedded tab characters could be pasted in to the addressbar. If a user were tricked in to copying a specially crafted URL in to the addressbar, an attacker could exploit this to conduct cross-site scripting (XSS) attacks. (CVE-2018-5143)
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