CVE-2024-56698 is a vulnerability identified in the Linux kernel's USB subsystem, specifically within the DesignWare Core USB3 (dwc3) gadget driver. The issue arises from improper handling of scatter-gather (SG) entries during USB request processing. In the affected code, the dwc3_request structure maintains a count of queued SG entries via the num_queued_sgs field. When a USB request is partially completed, the decrementing of num_queued_sgs does not accurately reflect the remaining SG entries to be processed, potentially leading to a state where the count is cleared prematurely. This incorrect accounting causes the driver to access non-existent SG entries, resulting in a null pointer dereference. Such a dereference typically leads to a kernel crash (kernel panic) or system instability, effectively causing a denial of service (DoS) condition. The vulnerability is rooted in the logic that prepares and queues SG entries for USB gadget requests, and the fix involves correctly verifying the number of remaining SG entries before accessing them. The vulnerability affects Linux kernel versions identified by the commit hash c96e6725db9d6a04ac1bee881e3034b636d9f71c and likely other versions incorporating this code. There are no known exploits in the wild at the time of publication, and no CVSS score has been assigned yet. The vulnerability does not require user interaction but does require the attacker to have the ability to interact with the USB gadget interface, which may be exposed on embedded devices or systems configured to act as USB devices.

For European organizations, the primary impact of CVE-2024-56698 is the potential for denial of service on Linux systems utilizing the dwc3 USB gadget driver. This is particularly relevant for organizations deploying embedded Linux devices, IoT gateways, or specialized hardware that expose USB gadget functionality, such as industrial control systems, telecommunications equipment, or network appliances. A successful exploitation could cause system crashes, leading to service interruptions, operational downtime, and potential loss of availability for critical infrastructure. While this vulnerability does not directly lead to privilege escalation or data exfiltration, the resulting instability could be leveraged as part of a broader attack chain, for example, to disrupt security monitoring or to create a distraction during other malicious activities. European sectors with high reliance on embedded Linux devices—such as manufacturing, automotive, healthcare, and telecommunications—may face increased risk. Additionally, organizations with strict uptime requirements or those operating critical infrastructure could experience significant operational and reputational damage if affected systems become unavailable.

To mitigate CVE-2024-56698, European organizations should: 1) Apply the latest Linux kernel patches that address this vulnerability as soon as they become available from trusted sources or Linux distribution vendors. 2) Identify and inventory all systems running Linux kernels with the affected dwc3 gadget driver, focusing on embedded devices and specialized hardware that expose USB gadget functionality. 3) Where patching is not immediately feasible, consider disabling USB gadget functionality if it is not required for operational purposes to reduce the attack surface. 4) Implement strict access controls and monitoring on USB interfaces to detect and prevent unauthorized interactions that could trigger the vulnerability. 5) Employ kernel hardening techniques such as kernel lockdown or seccomp filters to limit the impact of potential kernel crashes. 6) Monitor system logs and kernel crash reports for signs of exploitation attempts or instability related to USB gadget operations. 7) Coordinate with hardware vendors and Linux distribution maintainers to ensure timely updates and support for affected devices. These steps go beyond generic advice by emphasizing inventory management, interface control, and operational monitoring specific to the USB gadget subsystem.