15-Year-Old GhostLock Flaw Enables Root and Container Escape on Most Linux Distros

Researchers at Nebula Security disclosed GhostLock (CVE-2026-43499), a long-standing Linux kernel flaw (present since 2011) that allows a logged-in user on unpatched systems to gain full root privileges and break out of containers. The issue is triggered via ordinary local threading behavior with no special permissions or network access, making it a serious risk for multi-tenant hosts, cloud instances, CI runners, and shared environments. Nebula published working exploit code, underscoring the urgency of applying the latest kernel updates from affected distributions.