CVE-2023-54096 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
soundwire: fix enumeration completion
The soundwire subsystem uses two completion structures that allow drivers to wait for soundwire device to become enumerated on the bus and initialised by their drivers, respectively.
The code implementing the signalling is currently broken as it does not signal all current and future waiters and also uses the wrong reinitialisation function, which can potentially lead to memory corruption if there are still waiters on the queue.
Not signalling future waiters specifically breaks sound card probe deferrals as codec drivers can not tell that the soundwire device is already attached when being reprobed. Some codec runtime PM implementations suffer from similar problems as waiting for enumeration during resume can also timeout despite the device already having been enumerated.
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Analysis
by VulDB Data Team • 01/03/2026
The vulnerability identified as CVE-2023-54096 resides within the Linux kernel's soundwire subsystem, representing a critical flaw in the device enumeration and initialization process. This issue affects the proper functioning of soundwire bus devices that require enumeration before their drivers can complete initialization. The soundwire protocol operates as a high-speed serial bus designed for audio and multimedia applications, commonly used in modern computing devices for connecting audio codecs and other peripheral components. The subsystem employs completion structures as synchronization mechanisms that enable drivers to wait for specific events during device enumeration and initialization processes, ensuring proper device readiness before further operations commence.
The technical implementation flaw stems from improper handling of completion signaling mechanisms within the soundwire subsystem. Specifically, the code fails to properly signal all current and future waiters that are awaiting device enumeration completion, while simultaneously utilizing incorrect reinitialization functions for completion structures. This dual failure creates a scenario where completion objects may not properly reset their state, leading to potential memory corruption vulnerabilities when waiters remain on the queue. The root cause can be categorized under CWE-362, which describes concurrent execution using shared resource vulnerabilities, and CWE-398, which addresses code quality issues that may result in incorrect behavior. The improper signaling mechanism directly violates the expected behavior of synchronization primitives, creating a race condition where multiple threads or processes may attempt to access the same completion object in an inconsistent state.
The operational impact of this vulnerability extends beyond simple functional failures to potentially compromise system stability and device functionality. When sound card probe deferrals break due to the inability to signal future waiters, codec drivers cannot properly recognize that soundwire devices have already been attached during reprobe operations. This creates a cascading effect where audio subsystems may fail to initialize correctly, leading to missing audio devices or complete audio functionality loss. Additionally, codec runtime power management implementations suffer from similar issues, where waiting for enumeration during device resume operations may timeout even though the device has already been successfully enumerated. This results in unnecessary power management delays and potential system instability, particularly during device suspend/resume cycles. The vulnerability affects systems using soundwire buses for audio applications, including laptops, desktop computers, and embedded systems with audio peripherals, potentially impacting user experience through audio interruptions or complete audio subsystem failures.
Mitigation strategies for CVE-2023-54096 should focus on implementing proper completion signaling mechanisms and ensuring correct reinitialization of synchronization objects within the soundwire subsystem. The primary fix involves correcting the completion signaling logic to ensure all current and future waiters receive proper notification when device enumeration completes, while also using the appropriate reinitialization functions for completion structures. System administrators should apply the latest kernel updates that contain the patched soundwire subsystem implementation, which addresses the improper completion handling through corrected signaling mechanisms and proper state management. Organizations should prioritize updating systems running Linux kernels with soundwire support, particularly those in enterprise environments where audio functionality is critical. The vulnerability demonstrates the importance of proper synchronization primitive usage in kernel space, aligning with ATT&CK technique T1068 which involves privilege escalation through kernel vulnerabilities, and T1490 which covers denial of service through resource exhaustion or corruption. Regular kernel security audits should include verification of completion object usage patterns to prevent similar race condition vulnerabilities in other subsystems.