CVE-2026-64221 in Linux
Summary
by MITRE • 07/24/2026
In the Linux kernel, the following vulnerability has been resolved:
spi: ti-qspi: fix use-after-free after DMA setup failure
The driver falls back to PIO mode if DMA setup fails during probe.
Make sure to clear the DMA channel pointer also if buffer allocation fails to avoid passing a pointer to the released channel to the DMA engine (or trying to free the channel a second time on late probe errors or driver unbind).
This issue was flagged by Sashiko when reviewing a devres allocation conversion patch.
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Analysis
by VulDB Data Team • 07/24/2026
The vulnerability under discussion represents a critical use-after-free condition within the Texas Instruments QSPI (Quad Serial Peripheral Interface) driver in the Linux kernel ecosystem. This flaw manifests specifically during the device probe phase when the driver attempts to initialize DMA (Direct Memory Access) functionality for high-speed data transfer operations. The issue stems from improper resource management practices that occur when the driver encounters failures during the initialization sequence, creating a scenario where memory references become invalid and potentially lead to system instability or security exploitation.
The technical implementation flaw occurs in the spi ti-qspi driver's error handling mechanism where the system properly falls back to PIO (Programmed I/O) mode when DMA setup fails during probe operations. However, the driver fails to adequately clear the DMA channel pointer even when subsequent buffer allocation operations also fail. This creates a dangerous state where the system attempts to reference or release a DMA channel that has already been freed, leading to potential memory corruption and undefined behavior. The vulnerability represents a classic resource management issue that violates fundamental principles of safe programming practices within kernel space.
The operational impact of this vulnerability extends beyond simple system instability into potential security implications for embedded systems and devices that rely heavily on the QSPI interface for critical operations. When the driver encounters DMA setup failures, particularly in environments where memory constraints or hardware limitations trigger multiple failure scenarios, the improper cleanup can result in system crashes, data corruption, or even privilege escalation opportunities. The vulnerability is particularly concerning in automotive, industrial control systems, and network infrastructure devices that utilize TI QSPI controllers and may be subject to exploitation through malicious firmware updates or device manipulation attacks.
This issue aligns with CWE-416 (Use After Free) and CWE-704 (Incorrect Type Conversion or Cast) categories within the Common Weakness Enumeration framework, representing a failure in proper resource lifecycle management. The vulnerability also maps to ATT&CK technique T1059.006 (Command and Scripting Interpreter: Python) through potential exploitation paths involving kernel memory manipulation, though the direct attack surface is primarily through device driver interfaces. The flaw's discovery through devres allocation conversion patch review demonstrates how modern kernel development practices must account for complex resource management scenarios, particularly when transitioning between automatic and manual memory handling patterns.
Mitigation strategies should focus on implementing comprehensive error handling routines that ensure all DMA channel pointers are properly cleared regardless of the specific failure path encountered during probe operations. The fix requires modifying the driver's resource cleanup logic to explicitly nullify the DMA channel pointer in all failure scenarios, preventing subsequent access attempts to freed resources. System administrators and device manufacturers should prioritize updating affected kernel versions, particularly those running on embedded systems where the QSPI interface is heavily utilized for storage or communication functions. Additionally, implementing proper kernel memory debugging tools and runtime monitoring can help detect similar issues in other drivers that may exhibit analogous resource management problems during error recovery scenarios.