CVE-2026-33726: 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 Netw...

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.

Metrics

CVSS 3.1

4.3/10

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

EPSS Probability

0.24%

15.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Cilium	Cilium	< 1.17.14
Cilium	Cilium	>= 1.18.0, < 1.18.8
Cilium	Cilium	>= 1.19.0, < 1.19.2

References

https://docs.cilium.io/en/stable/network/concepts/routing/#routingTechnical Description
https://docs.cilium.io/en/stable/network/kubernetes/policy/#network-policyTechnical Description
https://docs.cilium.io/en/stable/network/servicemesh/l7-traffic-managementTechnical Description
https://docs.cilium.io/en/stable/operations/performance/tuning/#ebpf-host-routingTechnical Description
https://github.com/cilium/cilium/pull/44693Issue Tracking, Patch
https://github.com/cilium/cilium/security/advisories/GHSA-hxv8-4j4r-cqgvPatch, Vendor Advisory

Timeline

Published: Mar 27, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-33726?

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.

How severe is CVE-2026-33726?

CVE-2026-33726 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 0.24% probability of exploitation in the next 30 days.

How do I fix CVE-2026-33726?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.