CVE-2026-64342 in Linux
Summary
by MITRE • 07/25/2026
In the Linux kernel, the following vulnerability has been resolved:
USB: iowarrior: fix use-after-free on disconnect
Submitted write URBs are not stopped on close() and therefore need to be stopped unconditionally on disconnect() to avoid use-after-free in the completion handler.
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Analysis
by VulDB Data Team • 07/25/2026
The vulnerability under discussion involves a critical use-after-free condition in the Linux kernel's USB iowarrior driver implementation. This flaw exists within the device driver subsystem where submitted write USB Request Blocks are not properly terminated during device disconnection events, creating a dangerous race condition that can lead to memory corruption and potential privilege escalation.
The technical root cause stems from improper resource management in the USB iowarrior driver's disconnect handling mechanism. When a USB device is disconnected, the driver fails to unconditionally stop all pending write URBs that were submitted during the device's operational lifecycle. This oversight creates a scenario where completion handlers for these URBs may attempt to access memory locations that have already been freed or reallocated, resulting in undefined behavior and potential exploitation opportunities.
This vulnerability directly maps to CWE-416, which describes the use of freed memory condition, and represents a classic example of improper resource management in kernel space. The flaw is particularly concerning because it operates at the kernel level where such issues can lead to complete system compromise. The iowarrior driver specifically handles USB devices that implement the iowarrior protocol, commonly used for industrial automation and embedded systems applications.
The operational impact of this vulnerability extends beyond simple memory corruption as it creates a persistent attack surface that can be exploited by malicious actors with physical access to the target system or those able to manipulate USB device connections. Attackers could potentially leverage this use-after-free condition to execute arbitrary code with kernel privileges, effectively bypassing standard operating system security boundaries and gaining full control over the affected system.
From an ATT&CK framework perspective, this vulnerability aligns with techniques involving privilege escalation through kernel exploitation and supply chain attacks targeting device drivers. The mitigation strategy requires implementing proper URB cancellation mechanisms during device disconnection events, ensuring that all pending write operations are terminated before memory cleanup occurs. This fix should be applied across all versions of the Linux kernel where the iowarrior driver is present, with particular attention to embedded systems and industrial control environments that rely heavily on USB device connectivity.
The resolution involves modifying the disconnect handler to unconditionally cancel all pending URBs regardless of their state or completion status, ensuring proper cleanup before memory deallocation occurs. This approach aligns with kernel security best practices for resource management and prevents the race condition that enables the use-after-free scenario. The fix demonstrates the critical importance of proper synchronization and resource cleanup in kernel space drivers where memory safety violations can have catastrophic system-wide consequences.
Security researchers recommend immediate patch application across all affected Linux kernel versions, particularly in environments where USB devices are frequently connected and disconnected or where physical security is a concern. The vulnerability represents a significant risk to industrial control systems, embedded devices, and any computing environment where USB device drivers operate with elevated privileges, making it a priority for system administrators to address promptly through proper kernel updates and patch management procedures.