CVE-2023-52894 is a vulnerability identified in the Linux kernel's USB gadget subsystem, specifically within the function ncm_bitrate() used by the f_ncm (Function Network Control Model) driver. The vulnerability arises from a potential NULL pointer dereference when the code attempts to access the 'gadget' member of the 'usb_composite_dev' structure without verifying its validity. This leads to a kernel panic due to an invalid memory access at offset 0x5C, corresponding to the 'max_speed' field of the 'usb_gadget' structure. The issue was observed in an aarch64 GKI (Generic Kernel Image) 5.10.149-android13 device, though the crash is currently unreproducible. The root cause is that the function ncm_do_notify() calls ncm_bitrate() with a NULL pointer, which then calls gadget_is_superspeed(NULL), resulting in the kernel dereferencing a NULL pointer. The vulnerability is triggered during USB CDC NCM (Network Control Model) notifications, particularly when handling speed change events. The fix involves adding proper NULL pointer checks to prevent the kernel from panicking and instead safely returning a default value. This vulnerability affects Linux kernel versions including the tagged commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and is relevant to devices using the f_ncm USB gadget driver, commonly found in embedded and mobile devices running Linux or Android kernels. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet.

For European organizations, the impact of CVE-2023-52894 depends largely on their use of Linux-based embedded systems or Android devices that utilize the USB CDC NCM gadget driver. This vulnerability can cause kernel panics leading to denial of service (DoS) conditions on affected devices. In critical infrastructure sectors such as telecommunications, industrial control systems, or IoT deployments where Linux-based embedded devices are prevalent, this could result in service interruptions or device unavailability. Although the vulnerability does not appear to allow privilege escalation or arbitrary code execution, the resulting system crashes could disrupt operations, especially in environments relying on USB networking gadgets for connectivity or device management. The lack of known exploits reduces immediate risk, but the potential for DoS in embedded devices used in European enterprises and public sector deployments warrants attention. Additionally, Android devices running affected kernels could experience instability, impacting mobile workforce productivity or device reliability.

To mitigate CVE-2023-52894, European organizations should: 1) Identify and inventory devices running affected Linux kernel versions, especially those using the f_ncm USB gadget driver, including embedded systems and Android devices with GKI 5.10.149 or similar kernels. 2) Apply vendor-supplied patches or kernel updates that include the fix for this NULL pointer dereference. If patches are not yet available, consider disabling the f_ncm gadget driver if it is not required for device functionality to reduce attack surface. 3) Implement monitoring for kernel panics or USB gadget subsystem errors in device logs to detect potential exploitation attempts or instability. 4) For Android devices, ensure timely OS and kernel updates through managed device update programs. 5) In environments where USB gadget functionality is critical, conduct controlled testing of updated kernels to confirm stability and absence of regressions. 6) Employ network segmentation and device isolation for embedded systems to limit the impact of potential DoS conditions caused by this vulnerability. 7) Collaborate with device vendors and Linux kernel maintainers to track patch releases and advisories related to this vulnerability.