CVE-2023-53015 is a vulnerability identified in the Linux kernel's Human Interface Device (HID) subsystem, specifically related to the betopff driver. The issue arises from insufficient validation of the structure of output reports in the betopff_init() function. This function only verifies that the total sum of the report counts for each report field is at least 4, but it does not ensure that there are exactly 4 report fields as expected by the hid_betopff_play() function. Consequently, a malicious or malformed device advertising an output report with a single field but with 4 report counts can bypass this check. When such a report is processed by hid_betopff_play(), it leads to a NULL pointer dereference, causing the kernel to crash. This results in a denial of service (DoS) condition due to kernel panic or system instability. The vulnerability affects specific Linux kernel versions identified by the commit hash 52cd7785f3cdd2724f4efb5b21dbc75d6f9ccef4. There are no known exploits in the wild at the time of publication, and no CVSS score has been assigned yet. The root cause is a logic flaw in input validation within the HID driver, which can be triggered by connecting a specially crafted HID device or emulating such a device to send malformed output reports. This vulnerability highlights the importance of rigorous input validation in kernel drivers to prevent system crashes and potential exploitation vectors.

For European organizations, the primary impact of CVE-2023-53015 is the risk of denial of service on Linux-based systems that utilize the affected HID betopff driver. This could affect servers, workstations, or embedded devices running vulnerable Linux kernel versions. The kernel crash caused by the NULL pointer dereference can lead to system downtime, loss of availability, and potential disruption of critical services. Organizations relying on Linux for operational technology, industrial control systems, or endpoint devices with HID peripherals may experience interruptions. Although there is no evidence of remote code execution or privilege escalation, the DoS condition could be exploited by an attacker with physical or logical access to the device to cause repeated crashes, impacting business continuity. The lack of known exploits reduces immediate risk, but the vulnerability could be weaponized in targeted attacks or insider threat scenarios. Additionally, organizations with strict uptime requirements or those operating in sectors such as finance, healthcare, or critical infrastructure should prioritize mitigation to avoid service interruptions. The impact on confidentiality and integrity is minimal, but availability is significantly affected.

To mitigate CVE-2023-53015, European organizations should take the following specific actions: 1) Identify and inventory Linux systems running the affected kernel versions, especially those with HID betopff driver enabled. 2) Apply the official Linux kernel patches or updates that address this vulnerability as soon as they become available from trusted Linux distributions or the kernel maintainers. 3) If patching is not immediately possible, consider disabling or blacklisting the betopff HID driver module to prevent the vulnerable code from executing, especially on systems where the driver is not required. 4) Implement strict device control policies to restrict the connection of unauthorized or untrusted HID devices, using endpoint security solutions or USB device management tools. 5) Monitor system logs and kernel messages for signs of crashes or unusual HID device activity that could indicate attempted exploitation. 6) For environments with high security requirements, consider deploying kernel lockdown features or using security modules (e.g., SELinux, AppArmor) to limit the impact of kernel driver faults. 7) Educate IT and security teams about the vulnerability to ensure rapid response and incident handling if exploitation attempts are detected.