CVE-2024-26715 is a vulnerability identified in the Linux kernel's USB controller driver for the DesignWare Core USB3 (dwc3) gadget subsystem. The flaw arises from a race condition during the suspend operation of the USB gadget driver. Specifically, when a USB device is repeatedly unplugged and plugged in, two CPUs (or threads) may concurrently access and modify the dwc3 gadget driver's state. CPU1 executes gadget_unbind_driver, which clears the dwc->gadget_driver pointer, while CPU2 simultaneously executes dwc3_gadget_suspend and dwc3_disconnect_gadget, which check and use this pointer. Due to the timing, CPU2 may observe dwc->gadget_driver as non-NULL and proceed, but by the time it dereferences it, CPU1 has cleared it, leading to a NULL pointer dereference. This results in a kernel NULL pointer dereference vulnerability that can cause a denial of service (system crash) due to kernel panic. The vulnerability affects multiple Linux kernel versions identified by specific commit hashes. Although no known exploits are reported in the wild, the flaw is significant because it affects the USB gadget driver, which is commonly used in embedded devices, development boards, and some Linux-based systems that expose USB device functionality. The root cause is a lack of proper synchronization between concurrent CPU operations modifying and accessing the gadget driver state, leading to a use-after-free or NULL pointer dereference scenario. The vulnerability was publicly disclosed on April 3, 2024, and is marked as published by the Linux project. No CVSS score has been assigned yet.

For European organizations, the primary impact of CVE-2024-26715 is the potential for denial of service on Linux systems that utilize the dwc3 USB gadget driver. This includes embedded systems, IoT devices, industrial control systems, and development platforms that expose USB device functionality. A successful exploitation would cause the affected system's kernel to crash, leading to service interruptions, operational downtime, and potential loss of availability. Critical infrastructure sectors such as manufacturing, telecommunications, and transportation that rely on Linux-based embedded devices could be affected. While the vulnerability does not directly lead to privilege escalation or data breach, the resulting system instability could be leveraged as part of a broader attack to disrupt services or cause cascading failures. Additionally, organizations using Linux for USB device emulation or development may face increased risk during device testing or deployment. Since the vulnerability requires physical or logical USB plug/unplug activity, remote exploitation is less likely unless attackers have local access or can simulate USB device events remotely. However, the ease of triggering the race condition through repeated plug/unplug cycles makes it a practical denial-of-service vector.

To mitigate CVE-2024-26715, European organizations should: 1) Apply the latest Linux kernel patches that address this race condition in the dwc3 gadget driver as soon as they become available from trusted Linux distributions or the upstream kernel. 2) For embedded or IoT devices, coordinate with device vendors to ensure firmware and kernel updates include this fix. 3) Implement strict access controls to limit who can physically or logically interact with USB ports on critical systems to reduce the risk of malicious or accidental triggering of the vulnerability. 4) Monitor system logs and kernel messages for signs of USB-related kernel panics or crashes that may indicate exploitation attempts. 5) Consider disabling USB gadget functionality on systems where it is not required to reduce the attack surface. 6) For development environments, enforce safe testing procedures and avoid rapid plug/unplug cycles that could trigger the race condition. 7) Employ kernel hardening techniques such as kernel lockdown and secure boot to reduce the risk of exploitation and unauthorized kernel modifications. These measures go beyond generic advice by focusing on controlling USB interactions and ensuring timely patch management in embedded and Linux-based environments.