CVE-2023-54041 in Linux
Summary
by MITRE • 12/24/2025
In the Linux kernel, the following vulnerability has been resolved:
io_uring: fix memory leak when removing provided buffers
When removing provided buffers, io_buffer structs are not being disposed of, leading to a memory leak. They can't be freed individually, because they are allocated in page-sized groups. They need to be added to some free list instead, such as io_buffers_cache. All callers already hold the lock protecting it, apart from when destroying buffers, so had to extend the lock there.
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Analysis
by VulDB Data Team • 12/26/2025
The vulnerability identified as CVE-2023-54041 represents a critical memory management flaw within the Linux kernel's io_uring subsystem, specifically affecting how provided buffers are handled during removal operations. This issue resides in the kernel's asynchronous I/O framework that enables high-performance I/O operations through a ring buffer mechanism. The io_uring interface has become increasingly prevalent in modern Linux systems for applications requiring efficient I/O handling, making this vulnerability particularly concerning for system stability and resource management. The flaw manifests when the kernel attempts to remove provided buffers from io_uring operations, creating a scenario where memory allocated for these buffer structures remains unreleased, leading to gradual memory consumption over time.
The technical root cause of this vulnerability stems from improper memory deallocation within the io_uring buffer management system. When io_buffer structures are no longer needed, the kernel fails to properly dispose of them, resulting in a memory leak that accumulates with each buffer removal operation. These buffer structures are allocated in page-sized groups rather than individual allocations, which means they cannot be freed on a per-structure basis. The system maintains these buffers in a cache mechanism called io_buffers_cache, but the current implementation does not properly integrate the freed buffer structures back into this cache during the removal process. This design flaw creates a situation where memory that should be recycled for reuse remains allocated indefinitely, leading to progressive memory exhaustion.
The operational impact of this vulnerability extends beyond simple memory consumption, potentially causing system instability and performance degradation in environments heavily reliant on io_uring operations. Systems utilizing high-frequency I/O operations, such as database servers, web servers, or storage applications, would be particularly susceptible to memory exhaustion over time. The vulnerability affects the kernel's ability to efficiently manage system resources, potentially leading to system crashes, degraded performance, or forced reboots in severe cases. Attackers could potentially exploit this memory leak to cause denial of service conditions, particularly in systems where io_uring is heavily utilized or where memory resources are already constrained. The vulnerability also aligns with CWE-401, which specifically addresses improper resource management and memory leaks in software systems.
Mitigation strategies for CVE-2023-54041 focus on implementing proper buffer structure disposal and integration with the existing io_buffers_cache mechanism. The fix requires extending the lock protection during buffer destruction operations to ensure thread safety while adding freed buffer structures back to the appropriate cache. System administrators should prioritize applying kernel updates that contain the patched implementation, which properly handles the buffer lifecycle management by ensuring io_buffer structures are correctly returned to the io_buffers_cache instead of being leaked. Monitoring systems for memory usage patterns and implementing automated alerting for unusual memory consumption trends can help detect exploitation attempts or accumulation of leaked memory. Additionally, organizations should review their io_uring usage patterns to minimize the frequency of buffer allocation and deallocation operations where possible, though this represents a temporary workaround rather than a permanent fix. The vulnerability demonstrates the importance of proper resource management in kernel-level code and highlights the need for comprehensive testing of memory allocation and deallocation pathways in high-performance I/O subsystems. This issue also relates to ATT&CK technique T1490, which involves resource exhaustion through memory leaks and other resource consumption attacks that can be leveraged to disrupt system availability.