CVE-2026-33150

libfuse is the reference implementation of the Linux FUSE. From version 3.18.0 to before version 3.18.2, a use-after-free vulnerability in the iouring subsystem of libfuse allows a local attacker to crash FUSE filesystem processes and potentially execute arbitrary code. When iouring thread creation fails due to resource exhaustion (e.g., cgroup pids.max), fuseuringstart() frees the ring pool structure but stores the dangling pointer in the session state, leading to a use-after-free when the session shuts down. The trigger is reliable in containerized environments where cgroup pids.max limits naturally constrain thread creation. This issue has been patched in version 3.18.2.