CVE-2024-56368 is a vulnerability identified in the Linux kernel's ring buffer implementation, specifically within the __rb_map_vma function located in kernel/trace/ring_buffer.c. The flaw arises due to an integer overflow during the calculation of the number of pages (nr_pages) used for memory mapping of tracing buffers. The calculation in question is nr_pages = ((nr_subbufs + 1) << subbuf_order) - pgoff. Without proper bounds checking, this calculation can overflow, leading to an incorrect, smaller value for nr_pages. This results in a slab-out-of-bounds read, as the kernel attempts to access memory beyond the allocated buffer, triggering a KASAN (Kernel Address Sanitizer) error. The vulnerability was discovered and reported by syzbot, an automated kernel fuzzing tool, which detected a slab-out-of-bounds read during the execution of a test case involving mmap on the tracing buffer. The vulnerability affects Linux kernel version 6.13.0-rc2 and likely other versions with similar ring buffer code. The root cause is a missing check before the calculation to prevent overflow, which has been fixed in the patched kernel. Exploiting this vulnerability requires the ability to open and mmap the tracing buffer files under /sys/kernel/tracing, which typically requires elevated privileges or specific capabilities. The provided reproducer code demonstrates how an attacker or tester can trigger the overflow by opening the trace_pipe_raw file and performing an mmap with carefully chosen parameters. While no known exploits are currently reported in the wild, the vulnerability could potentially be leveraged for local privilege escalation or denial of service by causing kernel memory corruption or crashes. The flaw impacts kernel tracing infrastructure, which is used for debugging and performance monitoring, and thus may affect systems where tracing is enabled or accessible. The vulnerability does not have an assigned CVSS score yet, and no official patch links are provided in the data, but it is marked as resolved in recent kernel revisions.

For European organizations, the impact of CVE-2024-56368 depends largely on their use of Linux systems with kernel tracing enabled and accessible to unprivileged or semi-privileged users. Many enterprises, cloud providers, and data centers across Europe run Linux-based servers, often with kernel tracing enabled for diagnostics or performance monitoring. If an attacker gains local access to a vulnerable system, they could exploit this vulnerability to cause kernel memory corruption, leading to system instability, crashes (denial of service), or potentially escalate privileges to gain root access. This poses a significant risk to critical infrastructure, cloud services, and enterprise IT environments that rely on Linux servers. The vulnerability is particularly relevant for organizations that allow developers or users access to tracing interfaces or have containerized environments where capabilities might be misconfigured. Given the widespread use of Linux in European government, finance, telecommunications, and industrial sectors, exploitation could disrupt services, compromise data confidentiality and integrity, and impact availability. However, exploitation requires local access and some level of permissions, limiting remote attack vectors. The absence of known exploits in the wild suggests that immediate widespread attacks are unlikely, but the vulnerability should be treated seriously due to its kernel-level impact and potential for privilege escalation.

To mitigate CVE-2024-56368, European organizations should: 1) Update Linux kernels to the latest stable versions where the overflow check in __rb_map_vma has been implemented and the vulnerability resolved. Monitoring kernel release notes and applying security patches promptly is critical. 2) Restrict access to kernel tracing interfaces under /sys/kernel/tracing, ensuring only trusted administrators have permissions to open and mmap these files. Use strict file system permissions and Linux capabilities to limit exposure. 3) Audit container and virtualization environments to verify that tracing capabilities are not inadvertently exposed to unprivileged containers or users. 4) Employ kernel hardening features such as Kernel Address Sanitizer (KASAN) in testing environments to detect similar memory issues proactively. 5) Monitor system logs and kernel messages for unusual crashes or KASAN reports that may indicate exploitation attempts. 6) Implement robust local access controls and user privilege management to reduce the risk of local attackers exploiting this vulnerability. 7) Consider disabling kernel tracing features if not required for production systems, reducing the attack surface. These steps go beyond generic advice by focusing on controlling access to the vulnerable interface and ensuring timely patching.