USN-3516-1

It was discovered that speculative execution performed by modern CPUs could leak information through a timing side-channel attack, and that this could be exploited in web browser JavaScript engines. If a user were tricked in to opening a specially crafted website, an attacker could potentially exploit this to obtain sensitive information from other domains, bypassing same-origin restrictions. (CVE-2017-5715, CVE-2017-5753, CVE-2017-5754).