One-Character Linux Kernel Flaw Enables Local Root Access Exploits Now Public
A comprehensive, functional exploit for a Linux kernel use-after-free that enables an unauthorized local user to escalate to root and escape a container has been released by security researchers.
The kernel's nf_tables packet-filtering code contains the vulnerability, CVE-2026-23111, which was fixed upstream on February 5, 2026. Even though Exodus Intelligence's complete technical walkthrough was made public on June 8, FuzzingLabs provided an independent reproduction of the attack in April.
The upstream update eliminated the single stray character—an inverted check in nf_tables—that caused the vulnerability on a single line. The flaw is rated CVSS 7.8 (high) by Ubuntu. Update and restart if the patch is not yet included in the kernel package for your distribution.
A typical acces...