Executive brief
A vulnerability exists in the Zephyr operating system when running on Xtensa processors. The system fails to properly clean up internal memory management records when a memory domain is destroyed, leaving behind 'dangling' references. This can lead to a system crash or, in more complex scenarios, allow memory corruption that could bypass security protections between different applications. Exploiting this requires high-level administrative privileges on the device.
Technical details
A use-after-free vulnerability exists in arch/xtensa/core/ptables.c when CONFIG_USERSPACE and CONFIG_XTENSA_MMU are enabled. The function arch_mem_domain_deinit() fails to remove the domain's node from the global xtensa_domain_list before the caller-owned k_mem_domain storage is freed or reused. Subsequent memory mapping operations (arch_mem_map/unmap) traverse this stale list, leading to a NULL pointer dereference or a use-after-free where stale page-table pointers are used for writes. This can result in a denial of service or page-table corruption that undermines userspace isolation. The vulnerability is reachable only via privileged kernel code and was introduced in v4.4.0. It is fixed in the main branch and v4.4-branch by adding sys_slist_find_and_remove() to the deinitialization path.
Affected products
- Zephyr Project Zephyr OS 4.4.0
Timeline
- 2026-06-14: other: Embargo date
- 2026-06-16: disclosed: Advisory published by Zephyr Project