CVE-2026-93171 in Linux
Summary
by MITRE • 09/18/2026
In the Linux kernel, the following vulnerability has been resolved:
leds: lp5860: Fix a potential double-unlock
In lp5860_device_init(), if lp5860_init_dt() fails, an already unlocked mutex is unlocked another time.
Slightly rework how the lock is taken/released to avoid this potential double unlock.
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Analysis
by VulDB Data Team • 09/18/2026
The Linux kernel driver for the LP5860 LED controller contains a concurrency control flaw within its device initialization sequence that can lead to undefined behavior due to improper mutex management. Specifically, in the lp5860_device_init function, there is an error handling path where if the call to lp5860_init_dt fails, the code attempts to release a lock that has already been released or was never properly acquired in the current execution context. This scenario constitutes a double-unlock vulnerability, which violates fundamental principles of synchronization primitives and can result in kernel panics, race conditions, or other stability issues depending on how the underlying mutex implementation handles invalid unlock operations.
From a technical perspective, this issue stems from an imbalance in lock acquisition and release logic during error recovery paths. When lp5860_init_dt encounters an error condition, such as failing to parse device tree data or encountering hardware initialization failures, the control flow jumps to an exit label that attempts to unlock a mutex. However, if the mutex was already unlocked prior to this failure point, or if it was never locked in the first place due to early returns, executing another unlock operation leads to corruption of the internal state of the synchronization primitive. In many kernel implementations, unlocking an unheld lock can trigger assertions that crash the system, while in others it may silently corrupt data structures leading to subtle race conditions later during device operation.
The operational impact of this vulnerability is primarily related to system stability and reliability rather than direct security exploitation by external actors. A double-unlock typically results in a kernel oops or panic, causing an immediate denial of service for the affected system. While it does not directly allow privilege escalation or remote code execution, the instability introduced can disrupt critical services running on devices utilizing this LED controller hardware. Furthermore, if the corrupted mutex state is accessed concurrently by other threads, it could potentially lead to data races that might be exploited in more complex attack scenarios involving memory corruption primitives, although such exploitation would require significant additional conditions and knowledge of the specific kernel version and configuration.
This vulnerability aligns with CWE-667, which describes improper locking leading to race conditions or deadlocks, specifically manifesting here as a double-unlock scenario that corrupts synchronization state. In terms of the MITRE ATT&CK framework for enterprise security, this type of flaw falls under techniques related to resource exhaustion and denial of service, particularly within the context of local privilege escalation vectors where an attacker might trigger specific initialization sequences on embedded systems or servers with accessible hardware interfaces. The lack of proper error handling in kernel drivers is a common source of such issues, highlighting the importance of rigorous static analysis and code review for concurrency control mechanisms.
To mitigate this vulnerability, developers must ensure that lock acquisition and release are strictly paired and balanced across all execution paths, including error handlers. In the case of lp5860_device_init, the fix involves restructuring the initialization logic to guarantee that a mutex is only unlocked if it was successfully locked during that specific function invocation. This may involve using goto-based cleanup patterns where locks are acquired at the beginning and released in a single exit path after verifying their state, or employing helper functions that safely handle conditional unlocking. Additionally, integrating static analysis tools capable of detecting lock imbalance issues into the development workflow can help identify similar flaws before they reach production kernels. Regular updates to the Linux kernel ensure that such concurrency bugs are patched, maintaining system integrity and preventing potential denial-of-service conditions caused by improper synchronization primitives.