CVE-2024-1086 is a use-after-free vulnerability classified under CWE-416 found in the Linux kernel's netfilter subsystem, specifically within the nf_tables component. The vulnerability stems from the nft_verdict_init() function allowing positive values to be used as drop errors within the hook verdict. This improper validation leads to a scenario where the nf_hook_slow() function can trigger a double free condition when NF_DROP is issued with a drop error value that resembles NF_ACCEPT. This double free can corrupt kernel memory, enabling an attacker with local access and low privileges to escalate their privileges to root. The affected kernel version is 3.15, but similar code patterns may exist in other versions. The vulnerability does not require user interaction but does require local access and low privileges, making it a local privilege escalation vector. The CVSS v3.1 score is 7.8, indicating high severity, with impacts on confidentiality, integrity, and availability. No public exploits have been reported yet, but the vulnerability is serious due to the potential for full system compromise. The recommended mitigation is to upgrade the Linux kernel to a version that includes the fix introduced after commit f342de4e2f33e0e39165d8639387aa6c19dff660. Organizations should audit their Linux kernel versions and apply patches promptly to prevent exploitation.

For European organizations, this vulnerability poses a significant risk as it allows local attackers to escalate privileges to root, potentially leading to full system compromise. This can result in unauthorized access to sensitive data, disruption of critical services, and the ability to deploy further attacks such as ransomware or espionage. Enterprises relying on Linux-based servers, especially those in critical infrastructure, finance, telecommunications, and government sectors, could face operational disruptions and data breaches. The vulnerability affects confidentiality by allowing attackers to access protected information, integrity by enabling unauthorized modifications, and availability by potentially causing system crashes or denial of service. Since exploitation requires local access, insider threats or attackers who have already compromised a lower-privileged account are the primary concern. The lack of known exploits in the wild provides a window for proactive patching, but the high severity score underscores the urgency of mitigation.

1. Immediately identify and inventory all systems running Linux kernel version 3.15 or other potentially affected versions. 2. Upgrade the Linux kernel to a version that includes the fix beyond commit f342de4e2f33e0e39165d8639387aa6c19dff660. If a direct upgrade is not feasible, apply any available backported patches from your Linux distribution vendor. 3. Restrict local access to critical systems by enforcing strict access controls and monitoring for unusual local login attempts. 4. Implement robust endpoint detection and response (EDR) solutions to detect anomalous behavior indicative of privilege escalation attempts. 5. Regularly audit user privileges and remove unnecessary local accounts or privileges that could be exploited. 6. Educate system administrators and security teams about this vulnerability and the importance of timely patching. 7. Monitor security advisories from Linux kernel maintainers and distribution vendors for updates or additional mitigations. 8. Consider deploying kernel hardening features such as Kernel Address Space Layout Randomization (KASLR) and Control Flow Integrity (CFI) where supported to reduce exploitation likelihood.