Linux Kernel EUVD-2026-27558

Upgrade to patched Linux kernel versions immediately: 6.6.136 or later for 6.6.x series, 6.12.83 or later for 6.12.x series, 6.18.24 or later for 6.18.x series, 6.19.14 or later for 6.19.x series, or 7.0 for mainline users. Patches are available from the Linux kernel stable tree at https://git.kernel.org/stable/ with specific fix commits documented in the references. For systems where immediate kernel upgrade is not feasible, implement compensating controls: restrict local user access to trusted administrators only (reduces attack surface by eliminating PR:L threat actors), deploy mandatory access control frameworks (SELinux/AppArmor) with policies preventing unprivileged users from triggering epoll operations in sensitive contexts (adds defense layer but does not eliminate the race condition), and enable kernel address space layout randomization and other exploit mitigations to increase exploitation difficulty (note: determined local attackers with UAF primitives can often bypass ASLR). Monitor systems for abnormal epoll usage patterns or unexpected kernel panics in eventpoll code paths as potential exploitation indicators. Important: compensating controls only reduce risk - they do not fix the underlying race condition, so kernel patching remains the definitive remediation.