CVE-2026-10681 SMP race in `thread_idx_alloc()` lets concurrent `k_object_alloc(K_OBJ_THREAD)` callers share a kernel-object permission slot

In Zephyr's userspace dynamic-objects subsystem, threadidxalloc in kernel/userspace/userspace.c allocated a new thread permission index from the global threadidxmap bitmap without holding listslock. On SMP systems, two user-mode threads invoking the kobjectallocKOBJTHREAD syscall concurrently can...

CVE-2026-10667 SMP use-after-free in Zephyr `CONFIG_USERSPACE` dynamic kernel-object tracking, reachable from unprivileged user threads

Zephyr's dynamic kernel-object tracking kernel/userspace/userspace.c, formerly kernel/userspace.c maintains a doubly-linked list objlist of dynamically allocated kernel objects. Iteration over this list in kobjectwordlistforeach was performed under listslock using the SAFE iterator which caches t...