Firefox could be made to crash or run programs as your login if it opened a malicious website.
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, or execute arbitrary code. (CVE-2018-12375, CVE-2018-12376, CVE-2018-12377, CVE-2018-12378)
6 September 2018
A security issue affects these releases of Ubuntu and its derivatives:
Firefox could be made to crash or run programs as your login if it opened a malicious website.
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, or execute arbitrary code. (CVE-2018-12375, CVE-2018-12376, CVE-2018-12377, CVE-2018-12378)
It was discovered that if a user saved passwords before Firefox 58 and then later set a master password, an unencrypted copy of these passwords would still be accessible. A local user could exploit this to obtain sensitive information. (CVE-2018-12383)
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