CVE-2024-56757 in Linux
Summary
by MITRE • 01/06/2025
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: btusb: mediatek: add intf release flow when usb disconnect
MediaTek claim an special usb intr interface for ISO data transmission. The interface need to be released before unregistering hci device when usb disconnect. Removing BT usb dongle without properly releasing the interface may cause Kernel panic while unregister hci device.
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Analysis
by VulDB Data Team • 10/13/2025
This vulnerability exists in the Linux kernel's Bluetooth subsystem specifically within the btusb driver implementation for MediaTek USB Bluetooth adapters. The issue stems from improper handling of USB interface release sequences during device disconnection events, creating a potential kernel panic condition that can compromise system stability. The vulnerability affects devices that utilize MediaTek's proprietary USB interface for ISO (isochronous) data transmission, which requires special handling during the device removal process.
The technical flaw occurs when a Bluetooth USB dongle is physically removed from the system without the proper interface release sequence being executed. The MediaTek USB adapter implements a specialized interrupt interface specifically designed for ISO data transmission, which must be explicitly released before the HCI (Host Controller Interface) device can be safely unregistered from the system. When this release flow is omitted during USB disconnection, the kernel attempts to unregister the HCI device while the interrupt interface remains in an inconsistent state, leading to a kernel panic condition that can crash the entire operating system.
The operational impact of this vulnerability extends beyond simple system instability as it can result in complete system crashes during normal device removal operations. Attackers could potentially exploit this weakness by repeatedly unplugging and replugging Bluetooth USB devices to force kernel panics, leading to denial of service conditions that affect the entire system. The vulnerability is particularly concerning in embedded systems or devices where Bluetooth connectivity is critical for operation, as unexpected kernel panics could lead to complete system failure. This issue aligns with CWE-691, which addresses insufficient control flow management in kernel drivers, and represents a classic example of improper resource cleanup during device teardown operations.
Mitigation strategies should focus on implementing proper USB interface release sequences before HCI device unregistration, with the most effective approach being the patch that adds the required intf release flow as referenced in the CVE resolution. System administrators should ensure that all Linux kernel updates are applied promptly to address this vulnerability, particularly in environments where Bluetooth USB devices are frequently connected and disconnected. The fix demonstrates proper adherence to the ATT&CK framework's defense evasion techniques by ensuring complete resource cleanup during device removal, preventing potential exploitation through kernel-level denial of service attacks. Organizations should also implement monitoring solutions to detect kernel panic events that may indicate this vulnerability is being exploited in the wild, as the crash conditions can be leveraged to disrupt service availability.