# CVE-2026-14367: I3C IBI work-node free-list data race between ISR and workqueue thread

Status: published. Published: 2026-08-31. Updated: 2026-11-04.

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.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: zephyr) — https://github.com/zephyrproject-rtos/zephyr/commit/e87e7e2ac7c5ded0af3fb5934518cc5688e458cc

## Affected products and versions

- zephyrproject / zephyr (zephyr): ≥ 3.2.0; < 4.3.2 (affected, semver); ≥ 4.4.0; < 4.4.2 (affected, semver). Source: CNA: zephyr

## Severity and prioritization

- CVSS 3.1: 3.1 (low); CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L; source: CNA: zephyr

- CVSS 3.1: 3.1 (low); CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L; source: NVD: vulnerabilities@zephyrproject.org

- CISA KEV: No listing in collected sources

- EPSS: 0.14% as of 2026-11-03; percentile 3.07%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-362

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/zephyrproject-rtos/zephyr/commit/e87e7e2ac7c5ded0af3fb5934518cc5688e458cc (CNA: zephyr; patch)

- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-gfj5-gcxv-9jqm (CNA: zephyr)

- https://github.com/zephyrproject-rtos/zephyr/commit/e87e7e2ac7c5ded0af3fb5934518cc5688e458cc (vulnerabilities@zephyrproject.org)

- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-gfj5-gcxv-9jqm (vulnerabilities@zephyrproject.org)

## Provenance

- CNA: zephyr: https://www.cve.org/CVERecord?id=CVE-2026-14367; retrieved 2026-11-04; source updated 2026-11-04

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-14367; retrieved 2026-11-04; source updated 2026-11-04

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-14367; retrieved 2026-11-04; source updated Not reported

Revision: c494b72013baa783936174ea44eb6b15135437fd8429b1673d3f1f7170dab964

Canonical: https://y2.dev/cve/CVE-2026-14367

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