CVE-2026-33726

5.4 MEDIUM
Published: March 27, 2026 Modified: April 01, 2026
View on NVD

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://docs.cilium.io/en/stable/network/concepts/routing/#routing
Source: security-advisories@github.com
Technical Description
https://docs.cilium.io/en/stable/network/kubernetes/policy/#network-policy
Source: security-advisories@github.com
Technical Description
https://docs.cilium.io/en/stable/network/servicemesh/l7-traffic-management
Source: security-advisories@github.com
Technical Description
https://docs.cilium.io/en/stable/operations/performance/tuning/#ebpf-host-routing
Source: security-advisories@github.com
Technical Description
https://github.com/cilium/cilium/pull/44693
Source: security-advisories@github.com
Issue Tracking Patch
https://github.com/cilium/cilium/security/advisories/GHSA-hxv8-4j4r-cqgv
Source: security-advisories@github.com
Patch Vendor Advisory

6 reference(s) from NVD

Quick Stats

CVSS v3 Score
5.4 / 10.0
EPSS (Exploit Probability)
0.0%
1th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

cilium