CVE-2026-14367 I3C IBI work-node free-list data race between ISR and workqueue thread
An attacker with physical access to the I3C bus can trigger a race condition in the Zephyr RTOS IBI subsystem, causing crashes or potential memory corruption.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-14367?
CVE-2026-14367 is a low-severity vulnerability in zephyrproject zephyr, published on 31 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
The I3C IBI subsystem in drivers/i3c/i3c_ibi_workq.c hands out statically-allocated work nodes through a free-list i3c_ibi_work_nodes_free implemented as a plain sys_slist_t, which provides no synchronization. The allocation helpers (i3c_ibi_work_enqueue, i3c_ibi_work_enqueue_target_irq, i3c_ibi_work_enqueue_hotjoin, i3c_ibi_work_enqueue_controller_request, i3c_ibi_work_enqueue_cb) called sys_slist_get() directly from ISR context, while the workqueue handler i3c_ibi_work_handler() returned nodes with sys_slist_append() from the workqueue thread, with no lock on either side.
Because sys_slist_get() and sys_slist_append() are neither atomic nor interrupt-safe, an IBI interrupt that fires while the workqueue thread is mid-append (or a truly parallel access under CONFIG_SMP) races on the shared list. This corrupts the list linkage: a node may be handed to two consumers, a node may be lost, or the head/tail pointers may be left inconsistent so sys_slist_get() returns a stale or garbage pointer. In the double-hand-out case the subsequent memcpy(ibi_node, ibi_work, sizeof(*ibi_node)) overwrites a node still in flight; a garbage pointer turns the same memcpy into an out-of-bounds write.
The race is driven by I3C bus traffic — IBIs, hot-joins, and controller-role requests originate from target devices on the bus, and I3C supports hot-joining devices. An attacker controlling an I3C peripheral on the board's chip-to-chip bus can generate high-frequency interrupts timed to collide with the free operation. Exploitation requires physical access to the bus and winning a narrow timing window; the most realistic impact is a crash or hang (denial of service), with memory corruption possible but hard to control.
The fix wraps all free-list sys_slist_get()/sys_slist_append() operations in the new ibi_work_alloc()/ibi_work_free() helpers, each guarded by a k_spinlock (ibi_work_lock), closing the race across ISR and thread contexts.
Weakness: CWE-362
Which versions are affected by CVE-2026-14367?
How do I fix CVE-2026-14367?
No fix has been published for CVE-2026-14367 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-14367 being exploited?
There is no known exploitation of CVE-2026-14367 in the wild and no public exploit code.
Sources
Also known as GHSA-gfj5-gcxv-9jqm.