CVE-2023-52745 is a vulnerability identified in the Linux kernel related to the IP over InfiniBand (IPoIB) networking implementation, specifically affecting legacy IPoIB interfaces. The issue arises from incorrect handling of transmit (tx) and receive (rx) queue counts when creating child Partition Key (PKEY) interfaces over netlink. Some network devices do not support multiple tx and rx queues, but the vulnerable kernel code erroneously assigns multiple queues to child interfaces while the parent interface supports only a single queue. This mismatch leads to a kernel NULL pointer dereference and subsequent crash when traffic is transmitted over the affected PKEY interface. The vulnerability manifests as a kernel oops and system crash, impacting system stability and availability. The patch corrects this by enforcing a single queue count for legacy IPoIB interfaces at the earliest point in the interface creation process, preventing the mismatch and crash. The vulnerability affects multiple Linux kernel versions identified by specific commit hashes, and no known exploits have been reported in the wild as of the publication date. The vulnerability does not have an assigned CVSS score but is classified as a kernel-level denial of service triggered by malformed or unexpected network traffic on IPoIB interfaces.

For European organizations, the primary impact of CVE-2023-52745 is on system availability and reliability, particularly for those using Linux-based systems with IPoIB networking in high-performance computing (HPC), data center, or specialized networking environments. A successful exploitation leads to kernel crashes causing system downtime, which can disrupt critical services and operations. Confidentiality and integrity impacts are minimal as the vulnerability does not provide direct code execution or privilege escalation capabilities. However, availability loss in production or research environments relying on InfiniBand networking can lead to significant operational and financial consequences. Organizations running Linux kernels with legacy IPoIB support in sectors such as scientific research, telecommunications, financial services, and cloud infrastructure may experience service interruptions. The lack of known exploits reduces immediate risk, but the vulnerability should be addressed promptly to avoid potential future exploitation or accidental system crashes.

1. Apply the official Linux kernel patch that fixes the queue count handling for legacy IPoIB interfaces as soon as it becomes available in your distribution's kernel updates. 2. For environments where IPoIB is not required, consider disabling IPoIB support in the kernel configuration or unloading the relevant kernel modules to eliminate exposure. 3. Monitor kernel logs for oops or crash messages related to IPoIB interfaces to detect potential exploitation or accidental triggering. 4. In virtualized or containerized environments, ensure that virtual network devices do not expose legacy IPoIB interfaces unnecessarily. 5. Conduct thorough testing of network interface configurations when upgrading kernels to detect any regressions or misconfigurations related to queue handling. 6. Maintain up-to-date backups and implement robust system recovery procedures to minimize downtime in case of crashes. 7. Engage with Linux distribution vendors or maintainers to track patch availability and deployment status.