Critical Linux Kernel Flaw Allows Unprivileged Users to Gain Full Root Access

A critical Linux kernel vulnerability (CVE-2026-46331, “Pedit COW”) in the act_pedit traffic-control path allows unprivileged local users to gain root by exploiting a copy-on-write sequencing bug that can corrupt shared page-cache and patch in-memory ELF binaries; a public PoC exploit 'packet_edit_meme' appeared shortly after disclosure and multiple major distributions (RHEL, Debian, Ubuntu) are confirmed or reported vulnerable. The advisory recommends immediate kernel patching and rebooting as the only complete fix, with temporary mitigations including disabling the act_pedit module or unprivileged user namespaces, and warns that hosts should be treated as fully compromised if exploitation is suspected.