CVE-2026-33726 Cilium L7 proxy may bypass Kubernetes NetworkPolicy for same-node traffic
Attackers can bypass Kubernetes NetworkPolicy restrictions for same-node traffic in specific Cilium configurations, requiring a patch to restore enforcement.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-33726?
CVE-2026-33726 is a medium-severity missing authorization vulnerability in cilium, published on 27 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-33726?
10 open source packages ship an affected version, including github.com/cilium/cilium, cilium and cilium-operator. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/cilium/cilium Go | All versions | 1.17.14, 1.18.8, 1.19.2 |
github.com/cilium/cilium Go | All versions | 1.17.14 |
github.com/cilium/cilium Go | All versions | 1.17.14 |
github.com/cilium/cilium Go | From 1.18.0 | 1.18.8 |
github.com/cilium/cilium Go | From 1.18.0 | 1.18.8 |
github.com/cilium/cilium Go | From 1.19.0 | 1.19.2 |
4 more packages
github.com/cilium/cilium Go | From 1.19.0 | 1.19.2 |
cilium Bitnami | All versions | 1.17.14, 1.18.8, 1.19.2 |
cilium-operator Bitnami | All versions | 1.17.14, 1.18.8, 1.19.2 |
hubble-relay Bitnami | All versions | 1.17.14, 1.18.8, 1.19.2 |
Products include Cilium Cilium.
How do I fix CVE-2026-33726?
Upgrade github.com/cilium/cilium to a fixed version for your release line: 1.17.14, 1.18.8 or 1.19.2.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-33726 being exploited?
There is no known exploitation of CVE-2026-33726 in the wild and no public exploit code.
Other vulnerabilities in cilium
- CVE-2026-49445 Cilium: Sensitive information disclosure and cluster disruption via local Envoy admin socket access
- CVE-2022-29178 Incorrect Default Permissions in Cilium
- CVE-2024-28860 Insecure IPsec transport encryption in Cilium
- CVE-2026-41520 Cillium exposes sensitive information included in the cilium-bugtool debug archive
- CVE-2024-37307 Cilium leaks sensitive information in cilium-bugtool
Sources
Also known as BIT-cilium-2026-33726, BIT-cilium-operator-2026-33726, BIT-hubble-relay-2026-33726, CLEANSTART-2026-ZS52141, GHSA-hxv8-4j4r-cqgv, GO-2026-4856 and 18 more.