CVE-2026-68181 in Linux
Summary
by MITRE • 08/10/2026
In the Linux kernel, the following vulnerability has been resolved:
mei: bus: access mei_device under device_lock on cleanup
Fix couple of problems in mei_cl_bus_dev_release():
mei_cl_flush_queues() is running without lock. bus->file_list access after mei_dev_bus_put(bus) can become a use-after-free if this was the last reference to bus.
Protect queues cleanup and WARN traversal by device lock there to avoid the concurrent access problems. Move WARN traversal before mei_dev_bus_put(bus).
This file uses bus variable name for mei_device, adjust code of mei_cl_bus_dev_release() to use bus variable too.
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Analysis
by VulDB Data Team • 08/11/2026
The vulnerability in question affects the Linux kernel's MEI (Management Engine Interface) subsystem, specifically within the bus layer implementation. This issue resides in the mei_cl_bus_dev_release() function where improper locking mechanisms lead to potential race conditions and memory corruption scenarios. The MEI subsystem provides communication interfaces between the host system and Intel's Management Engine, making it a critical component for system management and security features including firmware updates and hardware monitoring.
The technical flaw manifests through improper synchronization during device cleanup operations. When mei_cl_bus_dev_release() executes, it calls mei_cl_flush_queues() without holding the necessary device_lock, creating a window where concurrent access can occur. Additionally, the function accesses bus->file_list after invoking mei_dev_bus_put(bus), which can result in use-after-free conditions when the bus reference count reaches zero. This particular sequence creates a scenario where memory previously freed by mei_dev_bus_put() might still be accessed during queue cleanup operations, leading to undefined behavior and potential exploitation.
The operational impact of this vulnerability extends beyond simple memory corruption, as it affects the stability and reliability of system management interfaces. Attackers could potentially exploit these race conditions to cause system crashes, data corruption, or in more sophisticated scenarios, achieve privilege escalation within the kernel space. The vulnerability particularly affects systems using Intel Management Engine interfaces where device cleanup operations are frequent, such as in server environments or systems with active firmware update mechanisms. This issue directly relates to CWE-362, which describes race conditions in concurrent programming, and aligns with ATT&CK technique T1059.006 for kernel-mode rootkit development through privilege escalation.
The fix implements proper locking mechanisms by protecting queue cleanup operations and WARN traversal with the device_lock, ensuring exclusive access during critical sections. The solution moves the WARN traversal before mei_dev_bus_put(bus) to prevent accessing freed memory structures. Additionally, code standardization occurs by adjusting variable naming conventions to consistently use 'bus' for mei_device references throughout mei_cl_bus_dev_release(). These changes align with best practices for kernel development and address the fundamental synchronization issues that led to the vulnerability, providing robust protection against concurrent access problems in the MEI subsystem's device cleanup path.