CVE-2024-23851 is a vulnerability identified in the Linux kernel up to version 6.7.1, located in the copy_params function of the device-mapper ioctl handler (drivers/md/dm-ioctl.c). The issue stems from a missing validation check on the param_kernel->data_size parameter before memory allocation. Specifically, the function can attempt to allocate a buffer larger than INT_MAX bytes, causing an integer overflow during size calculation. This overflow leads to an incorrect allocation size, which can result in a kernel crash due to memory corruption or failed allocation. The vulnerability is triggered through the ctl_ioctl interface, which is accessible to local users with limited privileges (PR:L). The attack vector requires local access but no user interaction is needed. The CVSS 3.1 score is 5.5 (medium severity), reflecting the limited scope and impact: no confidentiality or integrity loss, but high impact on availability due to potential denial of service. No known exploits have been reported in the wild, and no patches were linked at the time of publication, indicating that mitigation may require kernel updates or configuration changes. The underlying weakness corresponds to CWE-190 (Integer Overflow or Wraparound), a common issue in memory allocation routines. This vulnerability highlights the importance of rigorous input validation in kernel code, especially for ioctl handlers that interact with user space.

The primary impact of CVE-2024-23851 is a denial of service condition caused by a kernel crash when the vulnerable ioctl interface attempts to allocate an excessively large buffer. For European organizations, this could disrupt services running on Linux servers or devices using affected kernel versions, particularly those relying on device-mapper functionality. Critical infrastructure sectors such as telecommunications, energy, finance, and government services that operate Linux-based systems may experience outages or degraded performance. Since the vulnerability requires local access, the risk is higher in environments where multiple users have shell access or where attackers can gain limited user privileges through other means. Although confidentiality and integrity are not directly affected, the availability impact can lead to operational disruptions and potential cascading effects in interconnected systems. The absence of known exploits reduces immediate risk, but the medium severity score and kernel-level impact warrant proactive mitigation to prevent potential exploitation or accidental crashes.

To mitigate CVE-2024-23851, organizations should monitor for and apply Linux kernel updates that address this vulnerability as soon as patches become available. In the interim, restrict local user access to systems running affected kernel versions, especially limiting access to the device-mapper ioctl interface (ctl_ioctl). Employ strict user privilege management and consider using mandatory access controls (e.g., SELinux, AppArmor) to limit ioctl calls from untrusted users. Audit and monitor system logs for unusual ioctl activity or kernel crashes that may indicate exploitation attempts. For critical systems, consider isolating vulnerable hosts or using kernel hardening techniques such as grsecurity or kernel lockdown features. Additionally, maintain regular backups and implement robust incident response plans to quickly recover from potential denial of service events. Avoid running untrusted code or scripts that could trigger the vulnerability, and educate system administrators about the risks associated with local privilege misuse.