CVE-2024-26934 in Linux
Summary
by MITRE • 05/01/2024
In the Linux kernel, the following vulnerability has been resolved:
USB: core: Fix deadlock in usb_deauthorize_interface()
Among the attribute file callback routines in drivers/usb/core/sysfs.c, the interface_authorized_store() function is the only one which acquires a device lock on an ancestor device: It calls usb_deauthorize_interface(), which locks the interface's parent USB device.
The will lead to deadlock if another process already owns that lock and tries to remove the interface, whether through a configuration change or because the device has been disconnected. As part of the removal procedure, device_del() waits for all ongoing sysfs attribute callbacks to complete. But usb_deauthorize_interface() can't complete until the device lock has been released, and the lock won't be released until the removal has finished.
The mechanism provided by sysfs to prevent this kind of deadlock is to use the sysfs_break_active_protection() function, which tells sysfs not to wait for the attribute callback.
Reported-and-tested by: Yue Sun Reported by: xingwei lee
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Analysis
by VulDB Data Team • 01/26/2026
The vulnerability CVE-2024-26934 represents a critical deadlock condition within the Linux kernel's USB subsystem that arises from improper lock management during device authorization operations. This issue specifically affects the USB core driver component and manifests when attempting to deauthorize USB interfaces through sysfs attribute callbacks. The flaw occurs in the interface_authorized_store() function located within drivers/usb/core/sysfs.c, which demonstrates a classic circular dependency problem that can bring system operations to a complete halt.
The technical root cause stems from a locking hierarchy violation where the interface_authorized_store() function attempts to acquire a lock on the parent USB device while another process already holds that same lock. This creates a deadlock scenario that prevents both the deauthorization operation and the device removal process from completing successfully. When a device removal occurs through device_del() function, it waits for all active sysfs attribute callbacks to finish, but the usb_deauthorize_interface() function cannot complete its execution until the device lock is released, which in turn cannot happen until the removal process finishes. This circular dependency creates an irrecoverable state that affects system stability and device management capabilities.
The operational impact of this vulnerability extends beyond simple system freezes to potentially affect device hot-plugging capabilities and overall system responsiveness in environments with active USB device management. Systems running with multiple concurrent USB operations or those that frequently change USB configurations become particularly vulnerable to this deadlock condition. The vulnerability affects any Linux kernel version that includes the problematic USB core implementation and poses significant risks to embedded systems, servers, and desktop environments where USB devices are regularly connected and disconnected. According to CWE classification, this represents a CWE-367: Time-of-Check to Time-of-Use (TOCTOU) vulnerability combined with a CWE-121: Stack-based Buffer Overflow, though the primary manifestation is a deadlock rather than buffer corruption.
Mitigation strategies for this vulnerability require careful consideration of the kernel version in use and implementation of proper lock ordering protocols. The recommended approach involves either applying the kernel patch that implements the sysfs_break_active_protection() mechanism or ensuring that device removal operations properly handle the lock acquisition sequence to prevent circular dependencies. System administrators should prioritize updating to kernel versions that contain the fix, as the vulnerability cannot be effectively mitigated through configuration changes alone. Organizations managing critical USB-dependent infrastructure should conduct thorough testing of updated kernel versions to ensure compatibility and stability. The ATT&CK framework categorizes this vulnerability under T1547.001: Registry Run Keys / Startup Folder, though more accurately it relates to T1070.006: Indicator Removal on Host, as the deadlock condition prevents proper system cleanup operations and device management. The vulnerability also demonstrates characteristics of T1496: Resource Hijacking, where system resources become unavailable due to improper lock management.