Critical Bad Epoll Vulnerability Grants Root Access to Unprivileged Users

Bad Epoll (CVE-2026-46242) is a critical use-after-free flaw in the Linux epoll subsystem affecting kernel version 6.4 and later that enables unprivileged local users to gain root privileges. A reliable exploit with a 99% success rate has been demonstrated; although a patch was released on 2026-04-24, many distributions have not yet backported it, leaving desktops, servers, cloud workloads, and Android devices at risk and requiring immediate mitigation.