CVE-2024-26934 is a vulnerability identified in the Linux kernel's USB core subsystem, specifically within the sysfs interface handling code. The issue arises in the function interface_authorized_store(), which is responsible for managing the authorization state of USB interfaces. This function calls usb_deauthorize_interface(), which acquires a lock on the parent USB device. The vulnerability manifests as a potential deadlock scenario: if another process already holds the device lock and attempts to remove the interface (due to configuration changes or device disconnection), the removal process waits for all ongoing sysfs attribute callbacks to complete. However, usb_deauthorize_interface() cannot complete until the device lock is released, which in turn cannot happen until the removal finishes, creating a circular wait condition. The sysfs mechanism to prevent such deadlocks involves the sysfs_break_active_protection() function, which instructs sysfs not to wait for the attribute callback to finish, but this was not properly applied in this case. This deadlock can cause the affected system to hang or become unresponsive when USB devices are authorized or deauthorized, impacting system stability and availability. The vulnerability affects multiple versions of the Linux kernel, as indicated by the repeated commit hash references, and has been publicly disclosed without known exploits in the wild at this time. The flaw was responsibly reported and tested by security researchers Yue Sun and Xingwei Lee.

For European organizations, the impact of this vulnerability primarily concerns system availability and operational stability. Linux is widely used across Europe in enterprise servers, cloud infrastructure, embedded systems, and critical industrial environments. A deadlock in USB device handling could cause system hangs or require reboots, disrupting business operations, especially in environments relying on USB peripherals for critical functions (e.g., security tokens, input devices, or specialized hardware). While this vulnerability does not directly lead to privilege escalation or data leakage, the denial of service caused by deadlocks can affect service continuity, potentially impacting sectors such as finance, manufacturing, healthcare, and public services. Organizations with high USB device usage or automated device management workflows are at greater risk. Additionally, the lack of known exploits currently reduces immediate threat but does not eliminate the risk of future exploitation attempts, particularly in targeted attacks or sophisticated threat actor campaigns.

To mitigate this vulnerability, European organizations should prioritize updating their Linux kernel to the fixed version that addresses CVE-2024-26934 as soon as patches become available from their Linux distribution vendors. In environments where immediate patching is not feasible, administrators should consider minimizing USB device reconfiguration or removal operations, especially automated or scripted changes that might trigger the deadlock. Monitoring system logs for USB-related errors and implementing alerting for unusual USB device behavior can help detect potential deadlock conditions early. For critical systems, employing kernel live patching solutions can reduce downtime associated with patch deployment. Additionally, reviewing USB device usage policies and restricting unnecessary USB device connections can reduce exposure. Organizations should also ensure robust backup and recovery procedures to mitigate the impact of potential system hangs or crashes caused by this vulnerability.