Linux Kernel up to 7.2.5 arm_scmi scmi_child_dev_find race condition

Summaryinfo

A vulnerability marked as very critical has been reported in Linux Kernel up to 7.2.5. Affected by this vulnerability is the function scmi_child_dev_find of the component arm_scmi. Performing a manipulation results in race condition. This vulnerability is reported as CVE-2026-93081. The attack is possible to be carried out remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as very critical has been found in Linux Kernel up to 7.2.5. This affects the function scmi_child_dev_find of the component arm_scmi. The manipulation with an unknown input leads to a race condition vulnerability. CWE is classifying the issue as CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-93081 since 09/17/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/17/2026).

Upgrading to version 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch c59b3393df1348a12308aaabd5fbc58ed6b21cf5/6abe8fe36b29ff51d1a42c2f338972883f4751a5 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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