Ubuntu Security Notice 5186-2 - USN-5186-1 fixed vulnerabilities in Firefox. The update introduced several minor regressions. This update fixes the problem. Multiple security issues were discovered in Firefox. If a user were tricked into opening a specially crafted website, an attacker could potentially exploit these to cause a denial of service, obtain sensitive information, conduct spoofing attacks, bypass CSP restrictions, or execute arbitrary code. A security issue was discovered with the handling of WebExtension permissions. If a user were tricked into installing a specially crafted extension, an attacker could potentially exploit this to create and install a service worker that wouldn't be uninstalled with the extension. Various other issues were also addressed. Continue reading...