Bug 2440662 (CVE-2026-23221)

Summary: CVE-2026-23221 kernel: bus: fsl-mc: fix use-after-free in driver_override_show()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A use-after-free flaw was found in the Linux kernel's Freescale Management Complex (fsl-mc) bus driver. The driver_override_show() sysfs function reads the driver_override string without acquiring the device_lock, while driver_override_store() modifies and frees the string while holding the lock. This race condition can result in a use-after-free if the string is freed by a concurrent store operation while being read by the show function.
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Description OSIDB Bzimport 2026-02-18 16:03:07 UTC 
In the Linux kernel, the following vulnerability has been resolved:

bus: fsl-mc: fix use-after-free in driver_override_show()

The driver_override_show() function reads the driver_override string
without holding the device_lock. However, driver_override_store() uses
driver_set_override(), which modifies and frees the string while holding
the device_lock.

This can result in a concurrent use-after-free if the string is freed
by the store function while being read by the show function.

Fix this by holding the device_lock around the read operation.
Comment 1 Alexander B 2026-02-18 19:44:01 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026021806-CVE-2026-23221-43ae@gregkh/T