Qualys has disclosed a critical security flaw in the Linux operating system, identified as CVE-2026-46333, which has existed since 2016. This vulnerability allows unprivileged users to hijack privileged processes briefly, potentially granting them full admin access. The flaw affects default installations of several major Linux distributions, including Red Hat, SUSE, Debian, Ubuntu, and Fedora. The vulnerability scores a severity rating of 5.5/10, categorized as medium risk. It exploits a timing issue where Linux fails to cut off access to privileged processes quickly enough during shutdown, allowing attackers to access sensitive files and commands. Qualys has demonstrated working exploits on Debian 13, Ubuntu 24.04/26.04, and Fedora 43 and 44. The Linux kernel security team responded promptly, issuing a patch on May 14, 2026, just three days after the flaw was reported. Administrators are strongly advised to apply the kernel update immediately. For those unable to do so, adjusting the kernel.yama.ptrace_scope to 2 is recommended to block potential exploits. Additionally, systems with untrusted local users during the exposure period should consider their SSH keys and cached credentials compromised.