CVE-2024-11185 is a medium-severity vulnerability affecting Arista Networks EOS (Extensible Operating System) versions 4.29.0 through 4.33.0. The vulnerability arises from improper handling of ingress traffic on Layer 2 ports, where under certain conditions, traffic may be forwarded incorrectly across VLAN boundaries. Specifically, packets intended for one VLAN may be transmitted to ports associated with different VLANs, violating VLAN isolation and segmentation principles. This behavior corresponds to CWE-1189, which relates to improper enforcement of network segmentation policies. The vulnerability does not require authentication or user interaction and can be exploited remotely over the network (CVSS vector AV:N/AC:L/PR:N/UI:N). The impact affects confidentiality and integrity by allowing unauthorized access to VLAN-restricted traffic, potentially exposing sensitive data or enabling lateral movement within a network. Availability is not impacted. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability affects core network infrastructure devices running Arista EOS, which are commonly deployed in data centers and enterprise networks for high-performance switching and routing.

For European organizations, this vulnerability poses a significant risk to network segmentation and data confidentiality, especially in environments relying on Arista EOS for critical infrastructure such as financial institutions, telecommunications providers, cloud service operators, and large enterprises. Breach of VLAN isolation can lead to unauthorized data exposure, compliance violations (e.g., GDPR), and facilitate advanced persistent threats by enabling attackers to move laterally across segmented network zones. The risk is heightened in multi-tenant data centers and environments with strict segmentation policies. While availability is not directly affected, the compromise of VLAN boundaries undermines trust in network security controls and can lead to broader security incidents.

Organizations should immediately inventory their network devices to identify Arista EOS versions 4.29.0 through 4.33.0 in use. Until patches are available, network administrators should implement strict ingress filtering and VLAN access control lists (ACLs) to enforce segmentation at multiple layers, including physical port security and 802.1X authentication where feasible. Monitoring for anomalous VLAN traffic patterns and employing network segmentation validation tools can help detect exploitation attempts. Segregating critical VLANs on separate physical switches or using private VLANs may reduce exposure. Coordination with Arista Networks for timely patch deployment is essential once fixes are released. Additionally, updating network device configurations to disable unused ports and applying best practices for VLAN tagging and trunk port configuration can minimize risk.