Libfuse

libfuse is the reference implementation of the Linux FUSE. From version 3.18.0 to before version 3.18.2, a NULL pointer dereference and memory leak in fuse_uring_init_queue allows a local user to crash the FUSE daemon or cause resource exhaustion. When numa_alloc_local fails during io_uring queue entry setup, the code proceeds with NULL pointers. When fuse_uring_register_queue fails, NUMA allocations are leaked and the function incorrectly returns success. Only the io_uring transport is affected; the traditional /dev/fuse path is not affected. PoC confirmed with AddressSanitizer/LeakSanitizer. This issue has been patched in version 3.18.2.

Published: 2026-03-20T20:20:09.171Z
Updated: 2026-03-25T13:55:45.971Z

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 io_uring subsystem of libfuse allows a local attacker to crash FUSE filesystem processes and potentially execute arbitrary code. When io_uring thread creation fails due to resource exhaustion (e.g., cgroup pids.max), fuse_uring_start() 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.

Published: 2026-03-20T20:20:29.963Z
Updated: 2026-07-15T01:07:15.081Z