CVE-2025-38015 in Linux
Summary
by MITRE • 06/18/2025
In the Linux kernel, the following vulnerability has been resolved:
dmaengine: idxd: fix memory leak in error handling path of idxd_alloc
Memory allocated for idxd is not freed if an error occurs during idxd_alloc(). To fix it, free the allocated memory in the reverse order of allocation before exiting the function in case of an error.
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Analysis
by VulDB Data Team • 02/02/2026
This vulnerability resides within the Linux kernel's dmaengine subsystem, specifically affecting the Intel Data Center DAX (idxd) driver implementation. The flaw represents a classic memory management issue that occurs during error handling procedures, where allocated resources are not properly released when function execution encounters failure conditions. The idxd driver is responsible for managing hardware acceleration capabilities in Intel's data center platforms, enabling efficient data movement operations through dedicated hardware units. When the idxd_alloc function processes allocation requests for idxd structures, it performs multiple memory allocations to establish the necessary data structures for hardware operation. The vulnerability manifests when an error condition occurs during this allocation process, causing the function to exit prematurely without executing the proper cleanup routines that would normally release the previously allocated memory blocks.
The technical implementation of this flaw stems from improper error handling within the idxd_alloc function's control flow. During normal operation, the function allocates memory for various data structures including device context information, command buffers, and operational metadata required for idxd hardware management. When an error occurs at any point during this allocation sequence, the function should unwind all previously allocated resources to prevent memory leaks. However, the current implementation fails to execute this cleanup process, resulting in memory fragments that remain allocated in the system's memory space. The fix requires implementing a reverse order memory deallocation strategy where allocated memory blocks are freed in the exact opposite sequence of their allocation, ensuring that all resources are properly returned to the system before function termination. This approach follows established memory management best practices and prevents the accumulation of leaked memory that could eventually lead to system performance degradation or resource exhaustion.
The operational impact of this vulnerability extends beyond simple memory consumption issues, potentially affecting system stability and performance in environments heavily reliant on dmaengine operations. Memory leaks, while seemingly minor in isolation, can compound over time and lead to significant system resource constraints, particularly in high-throughput computing environments where idxd operations are frequent. The vulnerability affects systems utilizing Intel's data center acceleration hardware, which includes platforms supporting Intel Optane DC Persistent Memory and other advanced memory technologies. Attackers could potentially exploit this memory leak to cause denial of service conditions by exhausting available memory resources through repeated allocation operations. Additionally, the vulnerability may contribute to system instability during extended operation periods, as the accumulating memory leaks could eventually trigger kernel memory management subsystems to terminate processes or cause system crashes.
Mitigation strategies for this vulnerability should focus on immediate kernel updates to address the memory leak issue, while also implementing monitoring systems to detect abnormal memory consumption patterns. System administrators should prioritize applying the patched kernel version that resolves the idxd_alloc error handling path, as this represents a direct fix to the memory management flaw. The mitigation approach aligns with industry standards for memory management practices, specifically addressing CWE-401 which covers improper release of memory before reaching the end of its lifetime. Organizations should also implement memory monitoring tools to track memory usage patterns and identify potential exploitation attempts that might leverage this vulnerability for resource exhaustion attacks. The fix demonstrates proper defensive programming practices that align with ATT&CK technique T1499.004 which involves resource exhaustion through memory consumption. Regular system audits should include verification of memory allocation patterns and monitoring for persistent memory leaks that could indicate similar issues in other kernel subsystems. The vulnerability highlights the critical importance of proper error handling in kernel space operations where resource cleanup must be guaranteed regardless of execution path taken by the function.