CVE-2024-47695 is a vulnerability identified in the Linux kernel's RDMA (Remote Direct Memory Access) subsystem, specifically within the rtrs-clt (RDMA Transport Reliable Server client) component. The issue arises in the function init_conns(), which is responsible for initializing connections. During the connection setup, the code calls create_con() and create_cm() in a loop. If any of these calls fail, the cleanup process involves a loop that destroys tags and accesses memory indexed by a variable cid. The vulnerability is due to cid being set to clt_path->s.con_num, which can lead to out-of-bounds memory access during cleanup. This is a classic off-by-one or boundary error where the index exceeds the valid range of allocated resources. The patch corrects this by resetting cid to clt_path->s.con_num - 1, ensuring that the cleanup loop accesses memory within valid bounds. Out-of-bounds memory access in kernel space can lead to undefined behavior, including potential kernel crashes (denial of service), memory corruption, or escalation of privileges if exploited. However, there is no indication that this vulnerability has been exploited in the wild yet. The affected versions are specific Linux kernel commits identified by their hashes, suggesting this is a recent and targeted fix. The vulnerability does not have a CVSS score assigned yet, but it has been published and enriched by CISA, indicating its recognition by security authorities.

For European organizations, the impact of CVE-2024-47695 depends largely on their use of Linux systems with RDMA capabilities, which are common in high-performance computing, data centers, and enterprise environments. Exploitation could allow an attacker with local access or the ability to trigger the vulnerable code path to cause kernel crashes, leading to denial of service. More critically, out-of-bounds memory access in kernel space can sometimes be leveraged to execute arbitrary code or escalate privileges, potentially compromising the confidentiality and integrity of sensitive data. This is particularly concerning for sectors relying on Linux-based servers for critical infrastructure, cloud services, and research computing clusters. Given that RDMA is often used in performance-sensitive environments, disruption could affect financial services, telecommunications, and scientific research institutions prevalent in Europe. Although no known exploits exist yet, the vulnerability's presence in the kernel means that unpatched systems remain at risk, especially if attackers develop exploit techniques. The impact is heightened in environments where kernel-level security is paramount and where downtime or data breaches could have significant regulatory and financial consequences.

European organizations should prioritize updating their Linux kernels to the patched versions that address CVE-2024-47695 as soon as they become available from their Linux distribution vendors. Since the vulnerability involves kernel-level code, applying official kernel patches is the most effective mitigation. In environments where immediate patching is not feasible, organizations should restrict access to systems running RDMA-enabled Linux kernels to trusted users only, minimizing the risk of local exploitation. Monitoring kernel logs and system behavior for anomalies related to RDMA connections or unexpected crashes can provide early warning signs of exploitation attempts. Additionally, organizations should review and harden their RDMA usage policies, disabling RDMA features on systems where they are not required. For high-security environments, employing kernel-level security modules (e.g., SELinux, AppArmor) with strict policies may help contain potential exploitation. Finally, maintaining up-to-date incident response plans and ensuring backups are current will mitigate the impact of any successful attacks exploiting this vulnerability.