USN-4122-1 caused a regression in Firefox.
USN-4122-1 fixed vulnerabilities in Firefox. The update caused a regression that resulted in a crash when changing YouTube playback speed in some circumstances. This update fixes the problem.
8 October 2019
A security issue affects these releases of Ubuntu and its derivatives:
USN-4122-1 caused a regression in Firefox.
USN-4122-1 fixed vulnerabilities in Firefox. The update caused a regression that resulted in a crash when changing YouTube playback speed in some circumstances. 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 obtain sensitive information, bypass Content Security Policy (CSP) protections, bypass same-origin restrictions, conduct cross-site scripting (XSS) attacks, cause a denial of service, or execute arbitrary code. (CVE-2019-5849, CVE-2019-11734, CVE-2019-11735, CVE-2019-11737, CVE-2019-11738, CVE-2019-11740, CVE-2019-11742, CVE-2019-11743, CVE-2019-11744, CVE-2019-11746, CVE-2019-11748, CVE-2019-11749, CVE-2019-11750, CVE-2019-11752)
It was discovered that a compromised content process could log in to a malicious Firefox Sync account. An attacker could potentially exploit this, in combination with another vulnerability, to disable the sandbox. (CVE-2019-9812)
It was discovered that addons.mozilla.org and accounts.firefox.com could be loaded in to the same content process. An attacker could potentially exploit this, in combination with another vulnerability that allowed a cross-site scripting (XSS) attack, to modify browser settings. (CVE-2019-11741)
It was discovered that the "Forget about this site" feature in the history pane removes HTTP Strict Transport Security (HSTS) settings for sites on the pre-load list. An attacker could potentially exploit this to bypass the protections offered by HSTS. (CVE-2019-11747)
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