CVE-2026-122266 in aws-network-policy-agent
Summary
by MITRE • 11/05/2026
Improper isolation of shared resources in aws-network-policy-agent in Amazon EKS Network Policy Agent before 1.3.7 (VPC CNI before 1.22.3) might allow an authenticated adjacent user to bypass NetworkPolicy ingress enforcement on co-located pods via eBPF conntrack map poisoning using crafted AF_PACKET frames.
To remediate this issue, users should upgrade to Amazon VPC CNI Managed Add-on v1.22.3 or later (which includes Network Policy Agent v1.3.7).
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Analysis
by VulDB Data Team • 11/05/2026
The vulnerability identified in the aws-network-policy-agent component of Amazon EKS involves a critical failure in resource isolation mechanisms, specifically within the eBPF subsystem used for network policy enforcement. This flaw allows an authenticated user with access to co-located pods on the same node to manipulate shared kernel data structures through crafted AF_PACKET frames. The core technical issue stems from improper validation and boundary checks when handling connection tracking (conntrack) maps via eBPF programs. By poisoning these maps, an attacker can inject false or malformed entries that disrupt the stateful inspection logic employed by the network policy agent. This manipulation effectively blinds the enforcement mechanism to specific traffic patterns, allowing malicious packets to bypass ingress restrictions intended to isolate workloads according to defined security policies.
From a technical perspective, this vulnerability leverages the complexity of eBPF conntrack maps which are shared across multiple pods and processes on a node. The aws-network-policy-agent relies on these maps to track active connections and enforce allow or deny rules based on source IP, destination port, and protocol state. When an adjacent user crafts specific AF_PACKET frames that exploit race conditions or insufficient sanitization in the eBPF program logic, they can corrupt the conntrack entries. This corruption leads to a denial of service for legitimate traffic enforcement or, more critically, allows unauthorized ingress traffic to reach protected pods. The attack vector requires local network access and authentication within the cluster context, making it an adjacent threat that targets multi-tenant environments where strict isolation is paramount.
The operational impact of this vulnerability is severe in production Kubernetes clusters utilizing VPC CNI for networking. It undermines the fundamental security guarantee provided by NetworkPolicies, which are often used to implement zero-trust architectures within a cluster. An attacker who successfully exploits this flaw can communicate with pods that should be isolated from their namespace or tenant group. This could lead to unauthorized data exfiltration, lateral movement across service boundaries, or access to sensitive backend services such as databases and internal APIs. In multi-tenant environments, this breach of isolation compromises the security posture for all tenants sharing the same node infrastructure, potentially leading to regulatory non-compliance if protected data is exposed.
This vulnerability aligns with CWE-250, which describes execution with unnecessary privileges, and more specifically relates to improper input validation in system-level components that handle shared resources. In terms of MITRE ATT&CK mapping, this behavior corresponds to T1613, Remote Services: Cloud Infrastructure Discovery, as it facilitates lateral movement within the cloud environment by bypassing network segmentation controls. It also touches upon T1048, Exfiltration Over Alternative Protocol, if the attacker uses the bypassed connection channel for data theft. The exploitation technique involves manipulating kernel-level networking structures, which falls under techniques related to resource hijacking and evasion of security monitoring systems that rely on standard packet inspection methods.
To remediate this issue, organizations must upgrade the Amazon VPC CNI Managed Add-on to version 1.22.3 or later, which includes the patched aws-network-policy-agent v1.3.7. This update addresses the root cause by implementing stricter validation of eBPF map operations and enhancing isolation between pod-specific conntrack entries. Until the upgrade is performed, administrators should consider restricting network access to nodes running vulnerable versions using security groups at the cloud provider level rather than relying solely on Kubernetes NetworkPolicies for critical workloads. Additionally, monitoring for unusual patterns in AF_PACKET traffic or eBPF map modifications can help detect potential exploitation attempts during the transition period. Regular auditing of pod-to-pod communication flows and enforcing least-privilege network policies are essential complementary measures to mitigate risks associated with such infrastructure-level vulnerabilities.