CVE-2024-49952 is a vulnerability identified in the Linux kernel's netfilter subsystem, specifically within the nf_tables component responsible for packet filtering and network address translation. The issue arises from unsafe handling of the per-CPU variable nf_skb_duplicated during the execution of the nf_dup_ipv4() and nf_dup_ipv6() functions. These functions duplicate socket buffers (skbs) for IPv4 and IPv6 packets, respectively. The vulnerability is due to improper synchronization when writing to nf_skb_duplicated, which can lead to data corruption. The root cause is that disabling preemption alone is insufficient to protect the per-CPU variable; soft interrupts must also be disabled to ensure safe access. This flaw was discovered by syzbot, a kernel fuzzing tool, which reported a bug triggered by using __this_cpu_write() in preemptible code. The bug can cause kernel crashes or unpredictable behavior due to corrupted per-CPU data structures. The vulnerability affects Linux kernel versions prior to the patch that addresses this issue by disabling soft interrupts in addition to preemption during the critical section. Although no known exploits are currently reported in the wild, the flaw resides in a critical kernel networking component, making it a potential target for attackers aiming to cause denial of service or escalate privileges via kernel memory corruption. The vulnerability does not require user interaction but does require the ability to send or manipulate network packets processed by nf_tables, which is commonly enabled on many Linux systems for firewalling and packet filtering.

For European organizations, this vulnerability poses a risk primarily to servers, network appliances, and infrastructure devices running vulnerable Linux kernels with nf_tables enabled. Exploitation could lead to kernel crashes resulting in denial of service, impacting availability of critical services such as web hosting, cloud infrastructure, and internal network security appliances. In more sophisticated attack scenarios, memory corruption could be leveraged for privilege escalation or arbitrary code execution within the kernel context, potentially compromising confidentiality and integrity of sensitive data. Given the widespread use of Linux in European data centers, cloud providers, telecom infrastructure, and embedded systems, the vulnerability could affect a broad range of sectors including finance, government, healthcare, and telecommunications. The lack of known exploits reduces immediate risk, but the critical nature of kernel-level vulnerabilities necessitates prompt remediation to prevent future exploitation. Additionally, compliance with European cybersecurity regulations such as NIS2 and GDPR mandates timely patching of known vulnerabilities to maintain operational security and data protection standards.

European organizations should prioritize updating Linux kernels to versions that include the fix for CVE-2024-49952, which involves disabling soft interrupts alongside preemption when accessing the nf_skb_duplicated variable. Kernel patches are typically distributed through official Linux distribution channels; therefore, applying the latest security updates from trusted vendors (e.g., Debian, Ubuntu, Red Hat, SUSE) is essential. For environments where immediate patching is not feasible, organizations can consider temporarily disabling nf_tables or related netfilter features if they are not critical to operations, thereby reducing the attack surface. Network monitoring should be enhanced to detect unusual packet duplication or malformed packets that could trigger the vulnerability. Security teams should also audit firewall and packet filtering configurations to ensure minimal exposure. Finally, organizations should maintain robust incident response plans and kernel crash analysis capabilities to quickly identify and respond to potential exploitation attempts.