Cilium L7 proxy may bypass Kubernetes NetworkPolicy for same-node traffic
Summary
| CVE | CVE-2026-33726 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_M |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-27 01:16:20 UTC |
| Updated | 2026-04-01 15:53:30 UTC |
| Description | Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Prior to versions 1.17.14, 1.18.8, and 1.19.2, Ingress Network Policies are not enforced for traffic from pods to L7 Services (Envoy, GAMMA) with a local backend on the same node, when Per-Endpoint Routing is enabled and BPF Host Routing is disabled. Per-Endpoint Routing is disabled by default, but is automatically enabled in deployments using cloud IPAM, including Cilium ENI on EKS (`eni.enabled`), AlibabaCloud ENI (`alibabacloud.enabled`), Azure IPAM (`azure.enabled`, but not AKS BYOCNI), and some GKE deployments (`gke.enabled`; managed offerings such as GKE Dataplane V2 may use different defaults). It is typically not enabled in tunneled deployments, and chaining deployments are not affected. In practice, Amazon EKS with Cilium ENI mode is likely the most common affected environment. Versions 1.17.14, 1.18.8, and 1.19.2 contain a patch. There is currently no officially verified or comprehensive workaround for this issue. The only option would be to disable per-endpoint routes, but this will likely cause disruptions to ongoing connections, and potential conflicts if running in cloud providers. |
Risk And Classification
Primary CVSS: v3.1 4.3 MEDIUM from [email protected]
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Problem Types: CWE-284 | CWE-863 | CWE-284 CWE-284: Improper Access Control | CWE-863 CWE-863: Incorrect Authorization
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 4.3 | MEDIUM | CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| 3.1 | [email protected] | Secondary | 5.4 | MEDIUM | CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
| 3.1 | CNA | DECLARED | 5.4 | MEDIUM | CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N |
CVSS v3.1 Breakdown
Attack Vector
AdjacentAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
LowAvailability
NoneCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
NVD Known Affected Configurations (CPE 2.3)
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| docs.cilium.io/en/stable/network/kubernetes/policy | [email protected] | docs.cilium.io | Technical Description |
| docs.cilium.io/en/stable/network/concepts/routing | [email protected] | docs.cilium.io | Technical Description |
| docs.cilium.io/en/stable/network/servicemesh/l7-traffic-management | [email protected] | docs.cilium.io | Technical Description |
| github.com/cilium/cilium/pull/44693 | [email protected] | github.com | Issue Tracking, Patch |
| github.com/cilium/cilium/security/advisories/GHSA-hxv8-4j4r-cqgv | [email protected] | github.com | Patch, Vendor Advisory |
| docs.cilium.io/en/stable/operations/performance/tuning | [email protected] | docs.cilium.io | Technical Description |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.