CVE-2026-93081: firmware: arm_scmi: Fix SCMI device destroy lifetimes

Severity: unknown
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-17 · updated 2026-10-30

Description

In the Linux kernel, the following vulnerability has been resolved: firmware: arm_scmi: Fix SCMI device destroy lifetimes scmi_child_dev_find() drops the reference returned by device_find_child() before returning the scmi_device pointer. A concurrent unregister can then release the device while the destroy path is still using the returned pointer. Make the lookup helper return the device_find_child() reference and keep it until scmi_device_destroy() has finished unregistering the child. Also split device_unregister() in __scmi_device_destroy() so the SCMI bus ID is not made reusable until after device_del() has removed the old scmi_dev.N name from sysfs. This avoids a new SCMI device reusing the same ID while the old device is still registered. The final device release callback is also a possible cleanup path when SCMI children are deleted by driver core recursion rather than __scmi_device_destroy(). Release the SCMI bus ID from a common helper used by destroy, register-failure and final-release paths, and clear scmi_dev->id after freeing it so the final release cannot free the same ID again.

Affected products

Linux: from 6.1.138 before 6.1.191; from 6.6.90 before 6.6.160; from 6.12.28 before 6.12.114; from 5.15.182 before 5.16; from 6.14.6 before 6.15 — fixed in 6.1.191, 6.6.160, 6.12.114, 5.16, 6.15

How to fix

Upgrade to a fixed version: Linux 6.1.191, 6.6.160, 6.12.114, 5.16. Check the vendor advisory for mitigations.

References

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