CVE-2024-47711 is a use-after-free vulnerability in the Linux kernel's AF_UNIX socket implementation, specifically in the handling of out-of-band (OOB) data in unix_stream_recv_urg(). The flaw arises from improper management of OOB socket buffers (skb) during consecutive send and receive operations with MSG_OOB flags. The vulnerability scenario involves sending and receiving OOB data multiple times, where the consumed OOB skb remains in the receive queue, and subsequent calls to manage_oob() incorrectly return the next skb, which is also OOB. However, the internal pointer unix_sk(sk)->oob_skb is not cleared after freeing the skb, leading to a use-after-free condition when the kernel attempts to access this freed memory. This bug was uncovered following a recent commit that changed skb reference counting behavior for OOB skbs. The issue was detected by syzbot fuzzing infrastructure and confirmed by KASAN (Kernel Address Sanitizer) reports showing slab-use-after-free errors in net/unix/af_unix.c. The vulnerability affects Linux kernel versions prior to the patch and involves kernel memory corruption risks due to dangling pointers. Exploitation could allow an attacker with the ability to send and receive OOB data on AF_UNIX sockets to execute arbitrary code or cause denial of service via kernel crashes. No public exploits are known at this time, and the patch involves adding proper checks in manage_oob() to verify skb OOB status and clearing pointers appropriately. This vulnerability is significant because AF_UNIX sockets are widely used for interprocess communication on Linux systems, including many server and desktop environments.

For European organizations, this vulnerability poses a risk primarily to Linux-based systems that utilize AF_UNIX sockets for local IPC, which includes a vast majority of servers, cloud infrastructure, and embedded devices running Linux. Exploitation could lead to local privilege escalation or denial of service, impacting critical services and applications relying on stable kernel operation. Given the prevalence of Linux in European data centers, cloud providers, and enterprise environments, successful exploitation could disrupt business operations, compromise system integrity, or facilitate lateral movement by attackers. Although remote exploitation is unlikely without local access, insider threats or compromised accounts could leverage this flaw. The absence of known exploits reduces immediate risk, but the vulnerability's presence in kernel code means that unpatched systems remain exposed. Organizations in sectors with high Linux usage—such as finance, telecommunications, government, and technology—may face increased risk. Additionally, the vulnerability could affect containerized environments and virtualized infrastructure common in European cloud deployments, potentially impacting multi-tenant systems.

1. Apply the official Linux kernel patches that address CVE-2024-47711 as soon as they are available and tested for your environment. 2. For distributions that have not yet released patches, consider upgrading to the latest stable kernel versions that include the fix. 3. Restrict and monitor the use of AF_UNIX sockets with MSG_OOB operations, especially on multi-user systems, to limit potential exploitation vectors. 4. Employ kernel hardening features such as Kernel Address Sanitizer (KASAN) and other runtime protections in development or testing environments to detect similar issues early. 5. Implement strict access controls and auditing on systems to detect unusual local socket activity that could indicate exploitation attempts. 6. For critical systems, consider isolating services that require AF_UNIX sockets in hardened containers or virtual machines to minimize impact scope. 7. Maintain up-to-date intrusion detection and endpoint protection solutions capable of detecting anomalous kernel behavior or crashes. 8. Educate system administrators about the risks of local privilege escalation vulnerabilities and ensure timely patch management policies are enforced.