CVE-2023-54072 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
ALSA: pcm: Fix potential data race at PCM memory allocation helpers
The PCM memory allocation helpers have a sanity check against too many buffer allocations. However, the check is performed without a proper lock and the allocation isn't serialized; this allows user to allocate more memories than predefined max size.
Practically seen, this isn't really a big problem, as it's more or less some "soft limit" as a sanity check, and it's not possible to allocate unlimitedly. But it's still better to address this for more consistent behavior.
The patch covers the size check in do_alloc_pages() with the card->memory_mutex, and increases the allocated size there for preventing the further overflow. When the actual allocation fails, the size is decreased accordingly.
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Analysis
by VulDB Data Team • 01/02/2026
The vulnerability identified as CVE-2023-54072 resides within the Linux kernel's Advanced Linux Sound Architecture implementation, specifically affecting the PCM (Pulse Code Modulation) memory allocation subsystem. This issue represents a data race condition that occurs during the allocation process of PCM buffer memory, where the kernel fails to properly serialize access to shared resources during memory management operations. The flaw manifests in the pcm memory allocation helpers where a sanity check mechanism designed to prevent excessive buffer allocations operates without adequate locking mechanisms, creating a race condition that could potentially allow unauthorized memory consumption beyond predefined limits.
The technical implementation of this vulnerability stems from insufficient synchronization within the ALSA subsystem's PCM memory management functions. The do_alloc_pages() function contains a size validation check that should prevent buffer allocations from exceeding maximum allowable sizes, but this validation occurs without proper locking mechanisms such as the card->memory_mutex that should protect access to shared memory allocation resources. This lack of proper serialization means that multiple concurrent threads or processes can simultaneously access and modify memory allocation parameters, potentially allowing memory allocation to exceed the intended limits despite the presence of sanity checks. The vulnerability is classified under CWE-362, which specifically addresses Race Conditions in the Common Weakness Enumeration catalog, and aligns with ATT&CK technique T1499.001 for Resource Hijacking and T1059.001 for Command and Scripting Interpreter.
The operational impact of this vulnerability extends beyond simple memory consumption concerns, though the immediate practical risk appears limited due to the nature of the "soft limit" implementation. While the flaw does not enable unlimited memory allocation, it creates inconsistent behavior in memory management where the system's intended safeguards can be bypassed through concurrent access patterns. This inconsistency could potentially lead to system instability, particularly in environments where precise memory management is critical for audio processing performance. The vulnerability affects the reliability of the ALSA subsystem's memory allocation routines, which could result in unpredictable behavior during high-concurrency audio applications or in systems with multiple simultaneous audio streams. Attackers could potentially exploit this race condition to consume more memory than expected, potentially leading to resource exhaustion scenarios or degraded system performance. The patch resolves this issue by properly integrating the size validation check within the card->memory_mutex lock, ensuring that all allocation operations occur in a serialized manner while also implementing proper size adjustment mechanisms when allocation failures occur.
The mitigation strategy for CVE-2023-54072 involves applying the kernel patch that introduces proper locking mechanisms around the PCM memory allocation sanity checks. This patch ensures that the do_alloc_pages() function properly utilizes the card->memory_mutex to serialize access to memory allocation parameters, preventing concurrent modifications that could lead to exceeding the intended allocation limits. The fix also implements proper error handling that adjusts allocated sizes when actual allocation failures occur, maintaining system stability and preventing potential overflow conditions. System administrators should prioritize applying this kernel update across all affected systems, particularly those running audio-intensive workloads or serving multiple concurrent audio streams, as the race condition could compound under high-concurrency scenarios. The vulnerability demonstrates the importance of proper synchronization in kernel memory management subsystems and highlights how seemingly minor race conditions in low-level system components can create inconsistent behavior that impacts overall system reliability and resource management predictability.