CVE-2026-33726

MEDIUM EPSS 15.5%
Published Mar 27, 20263mo ago · Modified Jun 17, 20261w ago
4.3 CVSS 3.1
Medium
Find Similar
Published Mar 27, 2026 3mo ago
Last Modified Jun 17, 2026 1w ago

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.

CVSS Details

Base Score
4.3
Exploitability
2.8
Impact
1.4
Vector string
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Attack Vector Adjacent
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality None
Integrity Low
Availability None

Threat Intelligence

EPSS Exploit Probability
15.5% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 2

CWE-284
CWE-863 Incorrect Authorization Authorization

Affected Products 3

VendorProductVersionRange
ciliumcilium* <1.17.14
ciliumcilium*≥1.18.0  –  <1.18.8
ciliumcilium*≥1.19.0  –  <1.19.2

References 6

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

Remediation

  • github.com https://github.com/cilium/cilium/pull/44693
    Issue TrackingPatch
  • github.com https://github.com/cilium/cilium/security/advisories/GHSA-hxv8-4j4r-cqgv
    PatchVendor Advisory