CVE-2023-4459 is a vulnerability identified in the vmxnet3 network driver within Red Hat Enterprise Linux 8.2 Advanced Update Support. The issue is a NULL pointer dereference in the vmxnet3_rq_cleanup function located in drivers/net/vmxnet3/vmxnet3_drv.c. This flaw occurs because the driver lacks a proper sanity check during the cleanup phase of network receive queue operations. When triggered by a local attacker with standard user privileges, this can cause the kernel to dereference a NULL pointer, leading to a denial of service (DoS) by crashing or halting the affected system. The vulnerability requires local access but no elevated privileges beyond normal user rights and does not require user interaction. The impact is limited to availability, with no direct confidentiality or integrity compromise. The vmxnet3 driver is commonly used in virtualized environments, particularly with VMware virtual machines, making this vulnerability relevant for organizations running Red Hat Enterprise Linux 8.2 in such contexts. Although no known exploits have been reported in the wild, the flaw’s medium CVSS score of 5.5 reflects the moderate risk posed by potential DoS attacks that could disrupt critical services. The vulnerability was published on August 21, 2023, and no patches or exploit codes are currently publicly available, emphasizing the need for vigilance and timely updates once fixes are released.

For European organizations, this vulnerability primarily threatens system availability by enabling local attackers to cause kernel crashes and denial of service conditions. Organizations running Red Hat Enterprise Linux 8.2 in virtualized environments using the vmxnet3 driver—common in data centers and cloud infrastructures—may experience service interruptions, impacting business continuity and operational reliability. Critical sectors such as finance, healthcare, telecommunications, and government services that rely on stable virtualized Linux environments could face operational disruptions. While the vulnerability does not expose sensitive data or allow privilege escalation, the resulting downtime could lead to indirect financial losses, reputational damage, and regulatory compliance challenges, especially under stringent European data protection and operational resilience frameworks. The requirement for local access limits remote exploitation risks but does not eliminate insider threats or risks from compromised user accounts.

European organizations should implement the following specific mitigations: 1) Monitor Red Hat advisories closely and apply vendor patches promptly once available to address the NULL pointer dereference in vmxnet3. 2) Restrict local user access to systems running Red Hat Enterprise Linux 8.2 with vmxnet3 drivers, enforcing the principle of least privilege and using strong access controls to limit potential attackers. 3) Employ kernel crash monitoring and alerting tools to detect early signs of exploitation attempts or system instability related to vmxnet3. 4) In virtualized environments, consider isolating critical workloads and applying network segmentation to reduce the impact of potential DoS attacks. 5) Conduct regular vulnerability scans and penetration tests focusing on local privilege abuse scenarios to identify and remediate exposure. 6) Educate system administrators and security teams about this vulnerability and the importance of timely patch management. 7) If patching is delayed, consider temporary workarounds such as disabling or limiting the use of the vmxnet3 driver where feasible, or migrating affected workloads to alternative network drivers or kernel versions not impacted by this flaw.