CVE-2026-19575: The user-mode verification handler for the device_deinit() system call, z_vrfy_device_deinit() in kernel/device.c, validated its dev argument with K_SYSCALL

The user-mode verification handler for the device_deinit() system call, z_vrfy_device_deinit() in kernel/device.c, validated its dev argument with K_SYSCALL_OBJ

The user-mode verification handler for the device_deinit() system call, z_vrfy_device_deinit() in kernel/device.c, validated its dev argument with K_SYSCALL_OBJ_INIT(dev, K_OBJ_ANY). k_object_validate() short-circuits its type comparison when the requested type is K_OBJ_ANY, so the check reduced to "this pointer is the base address of some kernel object the calling thread has been granted" — the object's actual type was never compared, and K_SYSCALL_OBJ_INIT also skips the initialization-state check. The sibling handlers z_vrfy_device_init() and z_vrfy_device_is_ready() already used K_OBJ_DRIVER_ANY and were unaffected. A thread running in user mode can therefore pass any kernel object it holds permission on — most usefully a thread stack object obtained from the k_thread_stack_alloc() syscall or a statically defined K_THREAD_STACK it was granted in order to spawn a child user thread — whose backing memory is writable from user mode. z_impl_device_deinit() then interprets those attacker-written bytes as a struct device: it dereferences the state pointer read out of the object, calls the function pointer read out of ops.deinit, and on success writes through state again. The result

Description from the National Vulnerability Database, published by vulnerabilities@zephyrproject.org

What it means for a small business

If your business uses zephyr, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 0.12%, higher than 1% of CVEs. That’s low, but low isn’t zero, and the odds jump the day someone publishes an exploit. Scored October 28, 2026, updated daily.

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Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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