CVE-2026-64350 in Linux
Summary
by MITRE • 07/25/2026
In the Linux kernel, the following vulnerability has been resolved:
usb: cdnsp: fix stream context array leak in cdnsp_alloc_stream_info()
cdnsp_alloc_stream_info() allocates stream_info->stream_ctx_array with cdnsp_alloc_stream_ctx(). If a later stream ring allocation or stream mapping update fails, the error path frees the allocated stream rings and stream_rings array, but leaves stream_ctx_array allocated.
Free the stream context array before falling through to the stream_rings cleanup path.
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Analysis
by VulDB Data Team • 07/25/2026
The vulnerability described represents a memory management issue within the Linux kernel's USB subsystem, specifically affecting the Cadence USB controller driver implementation. This flaw exists in the cdnsp_alloc_stream_info() function which handles allocation of stream context arrays for USB transfer operations. The vulnerability manifests as a resource leak where allocated memory structures are not properly deallocated when subsequent allocation operations fail during the stream setup process.
The technical root cause stems from improper error handling within the stream allocation routine. When cdnsp_alloc_stream_info() calls cdnsp_alloc_stream_ctx() to allocate the stream_ctx_array, it subsequently attempts to allocate additional resources including stream rings and their associated arrays. If any of these later allocation steps fail, the function executes cleanup code that properly frees the stream rings and stream_rings array but omits cleanup of the previously allocated stream_ctx_array. This creates a memory leak that persists until the containing data structure is eventually freed or the system reboots.
From an operational perspective this vulnerability represents a denial-of-service risk that can accumulate over time, particularly in systems handling high volumes of USB transfers. The memory leak occurs during stream allocation operations which are part of normal USB controller initialization and transfer setup processes. As the kernel allocates new stream contexts for various USB devices and transfer types, each failed allocation leaves behind unreleased memory, gradually consuming system resources and potentially leading to system instability or complete resource exhaustion.
The vulnerability aligns with CWE-401, which specifically addresses improper deallocation of memory in software systems. This classification reflects the fundamental issue where allocated memory is not properly freed during error conditions, creating a resource leak that affects system stability. From an adversarial perspective this could be exploited to cause gradual resource depletion on systems with high USB activity, potentially leading to service disruption or denial-of-service conditions.
The fix implemented addresses this issue by ensuring proper cleanup ordering within the error path of cdnsp_alloc_stream_info(). The solution requires explicitly freeing the stream_ctx_array before proceeding to the cleanup of stream rings and associated arrays. This follows standard memory management best practices for error handling, where resources are freed in reverse order of allocation or at least before any potential fallback paths execute. The remediation ensures that all allocated memory structures are properly released regardless of where allocation failures occur during the multi-step allocation process.
This vulnerability demonstrates the importance of proper resource management in kernel space drivers where memory leaks can have cascading effects on system stability and performance. The fix reinforces defensive programming principles that emphasize complete resource cleanup even when error conditions occur, preventing accumulation of leaked resources over time. System administrators should ensure this patch is applied to all affected Linux kernel versions to maintain system reliability and prevent potential denial-of-service scenarios through gradual memory exhaustion.