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Fencer Intel
medium 5.4

CVE-2026-33726 json

Cilium L7 proxy may bypass Kubernetes NetworkPolicy for same-node traffic

published 7mo ago modified last mo. also BIT-cilium-2026-33726 , BIT-cilium-operator-2026-33726 , BIT-hubble-relay-2026-33726 , EUVD-2026-16503 , GHSA-hxv8-4j4r-cqgv , GO-2026-4856

cvss
5.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 17%
public exploits
0
none known

Summary

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.

Patch / fix

  • go github.com/cilium/cilium 1.17.14, 1.18.8, 1.19.2
  • bitnami cilium 1.17.14, 1.18.8, 1.19.2
  • bitnami cilium-operator 1.17.14, 1.18.8, 1.19.2
  • bitnami hubble-relay 1.17.14, 1.18.8, 1.19.2
  • cilium cilium 1.17.14, 1.18.8, 1.19.2
  • govulncheck-vulndb openSUSE Leap 15.6 0.0.20260326T203309-150000.1.155.2

suse advisories SUSE-SU-2026:1135-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
7mo ago

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 5.4 CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
GitHub 3.1 5.4 CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
NVD 3.1 4.3 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
OSV 3.1 4.3 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
go github.com/cilium/cilium
<1.17.14
>=1.18.0, <1.18.8
>=1.19.0, <1.19.2
1.17.14
1.18.8
1.19.2
bitnami cilium
<1.17.14
>=1.18.0, <1.18.8
>=1.19.0, <1.19.2
1.17.14
1.18.8
1.19.2
bitnami cilium-operator
<1.17.14
>=1.18.0, <1.18.8
>=1.19.0, <1.19.2
1.17.14
1.18.8
1.19.2
bitnami hubble-relay
<1.17.14
>=1.18.0, <1.18.8
>=1.19.0, <1.19.2
1.17.14
1.18.8
1.19.2

Affected products

  • cilium cilium

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.