CVE-2024-35831 is a vulnerability identified in the Linux kernel's io_uring subsystem, specifically related to the handling of pinned pages during the __io_uaddr_map function execution. The issue arises in the error handling path: if __io_uaddr_map fails after pages have been pinned, the error handler does not correctly release these pinned pages. This can lead to resource leakage, particularly pinned memory pages that remain allocated and unavailable for other processes or kernel operations. The vulnerability is triggered under conditions such as heavy memory fragmentation, which can cause __io_uaddr_map to fail and thus expose the improper release behavior. Although the reporter was unable to trigger the issue without artificially forcing a failure, the conditions for this failure can occur naturally in real-world scenarios where memory fragmentation is significant. The io_uring interface is a modern asynchronous I/O interface in Linux, widely used for high-performance applications, making this vulnerability relevant to systems relying on efficient I/O operations. The affected versions include specific Linux kernel commits identified by their hashes, indicating that this is a recent and specific code regression or flaw. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet. The vulnerability primarily impacts kernel memory management and resource handling, potentially leading to degraded system performance or denial of service due to resource exhaustion if pinned pages accumulate without release.

For European organizations, the impact of CVE-2024-35831 could be significant in environments where Linux servers are heavily utilized, especially in data centers, cloud infrastructure, and high-performance computing clusters. The improper release of pinned pages can lead to memory exhaustion, causing system instability or crashes, which in turn can disrupt critical services and applications. Organizations running workloads that depend on io_uring for asynchronous I/O, such as database servers, web servers, and container orchestration platforms, may experience degraded performance or outages. This could affect service availability and reliability, leading to potential operational downtime and financial losses. Additionally, while no direct exploitation for privilege escalation or code execution is indicated, the denial of service impact could be leveraged by attackers to disrupt services. European organizations with stringent uptime and service-level agreements (SLAs) may find this vulnerability particularly concerning. Furthermore, sectors such as finance, telecommunications, healthcare, and government, which rely heavily on Linux-based infrastructure, could face increased risk of service interruptions if the vulnerability is not addressed promptly.

To mitigate CVE-2024-35831, European organizations should prioritize updating their Linux kernel to the latest patched versions where this issue has been resolved. Since the vulnerability is related to kernel memory management, applying vendor-provided kernel patches or upgrading to a fixed kernel release is the most effective mitigation. Organizations should monitor kernel updates from their Linux distribution vendors (e.g., Debian, Ubuntu, Red Hat, SUSE) and apply them in a timely manner. Additionally, system administrators should monitor system memory usage and fragmentation levels, especially on servers with high I/O workloads using io_uring, to detect abnormal resource consumption that could indicate the presence of this issue. Implementing memory fragmentation reduction techniques, such as tuning kernel memory allocators or scheduling periodic system reboots during maintenance windows, may help reduce the likelihood of triggering the failure condition. For critical systems, consider isolating workloads or limiting the use of io_uring until patches are applied. Finally, maintain robust incident response and monitoring capabilities to detect potential denial of service symptoms related to memory exhaustion.