CVE-2026-78116: zephyr Vulnerability (CVSS 5.2)

Description

The Broadcom AFBR-S50 time-of-flight sensor driver double-completes an RTIO submission when sensor data evaluation fails. In data_ready_work_handler() (drivers/sensor/broadcom/afbr_s50/afbr_s50.c), a non-STATUS_OK return from Argus_EvaluateData() calls handle_error_on_result(), which finalises the request with rtio_iodev_sqe_err(), but execution then fell through to the tail of the function and finalised the very same struct rtio_iodev_sqe a second time with rtio_iodev_sqe_ok(). Unlike the other error branches in the same function, this one did not return. Both completion helpers reach rtio_executor_done() in subsys/rtio/rtio_executor.c, which returns the submission to the pool via rtio_sqe_pool_free() and, for streaming (multishot) submissions, also releases the RX buffer with rtio_release_buffer(). The second completion therefore reads a freed rtio_iodev_sqe, pushes the same mpsc node onto the submission queue while it is already on the pool free list — splicing the two lists together — and re-submits the freed request so the next measurement is written through an already-released buffer. For one-shot submissions it emits a spurious success completion carrying stale userdata and frees the same pool entry twice. The failure branch is driven by sensor conditions rather than by host software. The vendor API documents statuses such as ERROR_ARGUS_BIAS_VOLTAGE_REINIT and ERROR_ARGUS_LASER_MONITOR_INACTIVE as transient results of harsh ambient light, so a party in front of the optical sensor can provoke the invalid-data condition without any physical contact with the board or any software access; SPI transfer errors reach the same branch. In releases before the payload.Status check was dropped, ordinary sharp distance transitions in the sensor's field of view were sufficient. Impact is corruption of the RTIO submission pool and mempool bookkeeping: aliased submissions, writes through released buffers, and duplicate completions delivered to the application. The attacker does not control the corrupted content, so the practical consequence is memory corruption and loss of availability on devices that instantiate brcm,afbr-s50, rather than directed code execution. Only builds that enable this driver are affected.

Metrics

CVSS 3.1

5.2/10

CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

EPSS Probability

0.21%

10.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-415

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
zephyrproject	zephyr	>= 4.3.0, < 4.3.2; >= 4.4.0, < 4.5.0

References

Timeline

Published: Oct 21, 2026
Last Modified: Nov 4, 2026
Status: Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-78116?

The Broadcom AFBR-S50 time-of-flight sensor driver double-completes an RTIO submission when sensor data evaluation fails. In data_ready_work_handler() (drivers/sensor/broadcom/afbr_s50/afbr_s50.c), a non-STATUS_OK return from Argus_EvaluateData() calls handle_error_on_result(), which finalises the request with rtio_iodev_sqe_err(), but execution then fell through to the tail of the function and finalised the very same struct rtio_iodev_sqe a second time with rtio_iodev_sqe_ok(). Unlike the other error branches in the same function, this one did not return. Both completion helpers reach rtio_executor_done() in subsys/rtio/rtio_executor.c, which returns the submission to the pool via rtio_sqe_pool_free() and, for streaming (multishot) submissions, also releases the RX buffer with rtio_release_buffer(). The second completion therefore reads a freed rtio_iodev_sqe, pushes the same mpsc node onto the submission queue while it is already on the pool free list — splicing the two lists together — and re-submits the freed request so the next measurement is written through an already-released buffer. For one-shot submissions it emits a spurious success completion carrying stale userdata and frees the same pool entry twice. The failure branch is driven by sensor conditions rather than by host software. The vendor API documents statuses such as ERROR_ARGUS_BIAS_VOLTAGE_REINIT and ERROR_ARGUS_LASER_MONITOR_INACTIVE as transient results of harsh ambient light, so a party in front of the optical sensor can provoke the invalid-data condition without any physical contact with the board or any software access; SPI transfer errors reach the same branch. In releases before the payload.Status check was dropped, ordinary sharp distance transitions in the sensor's field of view were sufficient. Impact is corruption of the RTIO submission pool and mempool bookkeeping: aliased submissions, writes through released buffers, and duplicate completions delivered to the application. The attacker does not control the corrupted content, so the practical consequence is memory corruption and loss of availability on devices that instantiate brcm,afbr-s50, rather than directed code execution. Only builds that enable this driver are affected.

How severe is CVE-2026-78116?

CVE-2026-78116 has a CVSS score of 5.2/10 (MEDIUM severity). The EPSS model estimates a 0.21% probability of exploitation in the next 30 days.

How do I fix CVE-2026-78116?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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