CVE-2023-54123 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
md/raid10: fix memleak for 'conf->bio_split'
In the error path of raid10_run(), 'conf' need be freed, however, 'conf->bio_split' is missed and memory will be leaked.
Since there are 3 places to free 'conf', factor out a helper to fix the problem.
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Analysis
by VulDB Data Team • 01/03/2026
The vulnerability CVE-2023-54123 represents a memory leak issue within the Linux kernel's md RAID subsystem, specifically affecting the raid10 configuration. This flaw exists in the md/raid10 module where the kernel handles RAID10 storage configurations, which are commonly used for data redundancy and performance enhancement in enterprise storage environments. The memory leak occurs during error handling scenarios when the kernel attempts to clean up resources after a failure in the raid10_run() function, creating a condition that can lead to gradual memory consumption over time.
The technical root cause of this vulnerability lies in the improper cleanup of memory resources within the error path of the raid10_run() function. When an error occurs during RAID10 initialization or operation, the system attempts to free the configuration structure 'conf' but fails to properly release the 'conf->bio_split' component. This bio_split structure contains I/O bio requests that are used for handling data operations in the RAID10 configuration. The memory leak manifests because the cleanup process is duplicated across three different code paths, but only one of these paths correctly handles the bio_split memory release, leading to a resource leak that accumulates over time.
The operational impact of this memory leak vulnerability can be significant in production environments where RAID10 configurations are heavily utilized. As the system continues to encounter errors or perform operations that trigger the problematic code path, the leaked memory accumulates, potentially leading to system performance degradation, reduced available memory for other processes, and in severe cases, system instability or memory exhaustion. This vulnerability affects systems running Linux kernel versions that include the affected md/raid10 module, particularly those implementing RAID10 storage configurations in enterprise or server environments where continuous operation and memory efficiency are critical. The issue is classified under CWE-401 as a failure to release memory allocated on the heap, which directly relates to the improper resource management in the error handling code.
The fix implemented for this vulnerability addresses the root cause by creating a dedicated helper function to manage the cleanup of the 'conf' structure and its associated components. This approach ensures that regardless of which error path is taken, all memory resources including the bio_split component are properly released. The solution follows best practices for resource management and aligns with the principle of least privilege and proper cleanup in kernel space operations. This remediation prevents the accumulation of memory leaks that could otherwise compromise system stability and performance over extended periods of operation. The fix demonstrates proper adherence to memory management principles and represents a standard approach for addressing resource leaks in kernel modules, particularly those involving complex error handling scenarios in storage subsystems that are critical to system operation and data integrity.