A recently disclosed Linux kernel vulnerability, tracked as CVE-2026-46242, known as 'Bad Epoll', has been made public along with proof-of-concept (PoC) exploit code. This flaw allows unprivileged processes to gain root access on systems running kernel versions 6.4 and newer, including certain Android devices. The vulnerability is a race-condition use-after-free bug within the epoll mechanism that can lead to serious security breaches, such as leaking kernel memory.
Discovered by researcher Jaeyoung Chung, this vulnerability was reported as a zero-day and took an unusually long time to patch, prompting concerns about the Linux kernel’s response to security threats.