CVE-2024-47674 is a vulnerability identified in the Linux kernel's memory management subsystem, specifically related to the handling of PFN (Page Frame Number) mappings during error conditions in the mmap() system call. PFN mappings differ from typical memory mappings because they lack explicit lifetime management or reference counting for the underlying physical pages ('struct page'). This design choice, while intentional for performance and architectural reasons, introduces complexity in error handling. The vulnerability arises when partial PFN mappings are not properly cleaned up in the correct order during error scenarios. Improper cleanup can lead to stale or dangling page table entries (PTEs) that reference physical memory which may have already been freed. This can cause use-after-free conditions, potentially leading to memory corruption, system instability, or privilege escalation if exploited. The fix involves ensuring that any partial PFN mappings are torn down early and completely before other error handling proceeds, preventing the existence of invalid page table entries. The vulnerability affects multiple versions of the Linux kernel identified by the commit hash 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2. As of the published date (October 15, 2024), there are no known exploits in the wild. The vulnerability does not have an assigned CVSS score yet, but it is recognized by the Linux project and CISA has enriched the information, indicating its significance.

For European organizations, this vulnerability poses a risk primarily to systems running vulnerable Linux kernel versions. Linux is widely used across Europe in enterprise servers, cloud infrastructure, telecommunications, and critical infrastructure systems. Exploitation could allow attackers to cause system crashes or potentially escalate privileges by exploiting memory corruption from stale PFN mappings. This could lead to unauthorized access, data breaches, or disruption of services. Given the kernel-level nature of the vulnerability, successful exploitation could compromise the confidentiality, integrity, and availability of affected systems. Organizations relying on Linux-based infrastructure, including public sector entities, financial institutions, and technology providers, could face operational disruptions or security breaches if the vulnerability is exploited. However, the absence of known exploits and the complexity of triggering this condition may limit immediate widespread impact. Nonetheless, the vulnerability warrants prompt attention due to the critical role of the Linux kernel in system security and stability.

European organizations should prioritize updating their Linux kernel to the patched version that addresses CVE-2024-47674 as soon as it becomes available. Kernel updates should be tested and deployed promptly in all environments, especially production and critical systems. For environments where immediate patching is not feasible, organizations should monitor kernel-related logs for unusual memory management errors or system crashes that could indicate exploitation attempts. Employing kernel hardening techniques such as Kernel Address Space Layout Randomization (KASLR), Control Flow Integrity (CFI), and enabling kernel lockdown features can reduce exploitation risk. Additionally, restricting mmap() usage to trusted applications and enforcing strict access controls can limit exposure. Organizations should also maintain robust incident detection and response capabilities to quickly identify and mitigate any exploitation attempts. Collaboration with Linux distribution vendors for timely patch releases and guidance is essential. Finally, conducting thorough vulnerability assessments and penetration testing focused on kernel memory management can help identify residual risks.