CVE-2024-53131 is a vulnerability identified in the Linux kernel, specifically affecting the nilfs2 filesystem implementation. The issue arises from a null pointer dereference in the block_touch_buffer tracepoint, which is triggered when the touch_buffer() function is called from __nilfs_get_folio_block(). The root cause is that the tracepoint references the dev_t member bh->b_bdev->bd_dev without verifying if the buffer head (bh) has a valid pointer to a block_device structure. In the current kernel implementation, the block_device structure is only assigned after the function returns to the caller, leading to a potential null pointer dereference or a general protection fault, especially when Kernel Address Sanitizer (KASAN) is enabled. The vulnerability is due to the unnecessary call to touch_buffer(), which was originally intended to mark the folio/page owning the buffer head as accessed. However, since the folio/page marking was optimized and reimplemented, this call became redundant. The patch resolves the issue by removing the touch_buffer() call in this context, thereby preventing the null pointer dereference. This vulnerability affects Linux kernel versions containing the specified commit hash 5305cb830834549b9203ad4d009ad5483c5e293f and potentially other versions using the nilfs2 filesystem with the affected tracepoints. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet.

For European organizations, the impact of CVE-2024-53131 depends largely on the deployment of Linux systems utilizing the nilfs2 filesystem, which is less common compared to other filesystems like ext4 or XFS. However, Linux is widely used across European enterprises, government agencies, and critical infrastructure sectors. A null pointer dereference vulnerability can lead to system crashes (denial of service) or kernel panics, potentially disrupting services and operations. In environments where KASAN is enabled, the vulnerability may cause general protection faults, increasing system instability. Although this vulnerability does not directly allow code execution or privilege escalation, the resulting denial of service could impact availability of critical systems, especially those running specialized Linux distributions or embedded systems using nilfs2. The lack of known exploits reduces immediate risk, but unpatched systems remain vulnerable to potential future exploitation. Organizations relying on Linux kernel tracepoints for debugging or monitoring may also experience unexpected system faults, affecting operational reliability.

European organizations should prioritize applying the official Linux kernel patches that remove the problematic touch_buffer() call in the nilfs2 filesystem code. Specifically, updating to the latest stable kernel versions that include the fix for CVE-2024-53131 is essential. For systems where immediate patching is not feasible, disabling the "block:block_touch_buffer" tracepoint can mitigate the risk by preventing the vulnerable code path from being executed. Organizations should audit their Linux deployments to identify usage of nilfs2 and block-related tracepoints, especially in production and critical environments. Additionally, enabling kernel crash dump mechanisms and monitoring for kernel panics can help detect exploitation attempts or crashes related to this vulnerability. Since KASAN increases fault sensitivity, it should be used primarily in testing environments rather than production. Finally, maintaining robust backup and recovery procedures will minimize operational impact in case of denial of service incidents.