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Fencer Intel
medium 6.1

CVE-2026-26963 json

Cilium may not enforce host firewall policies when Native Routing, WireGuard and Node Encryption are enabled

published 8mo ago modified 2mo ago also BIT-cilium-2026-26963 , BIT-cilium-operator-2026-26963 , BIT-hubble-relay-2026-26963 , EUVD-2026-8407 , GHSA-5r23-prx4-mqg3 , GO-2026-4522

cvss
6.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 3%
public exploits
0
none known

Summary

Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Versions 1.18.0 through 1.18.5 will incorrectly permit traffic from Pods on other nodes when Native Routing, WireGuard and Node Encryption are enabled. This issue has been fixed in version 1.18.6.

Patch / fix

  • go github.com/cilium/cilium 1.18.6
  • bitnami cilium 1.18.6
  • bitnami cilium-operator 1.18.6
  • bitnami hubble-relay 1.18.6
  • cilium cilium 1.18.6
  • govulncheck-vulndb openSUSE Leap 15.6 0.0.20260226T182644-150000.1.149.1

suse advisories SUSE-SU-2026:0757-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

Is CVE-2026-26963 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-26963 updated cvss 6.1

cilium: Cilium: Information disclosure via incorrect traffic permitting with specific network configurations

  • Red Hat Confidential Compute Attestation openshift-sandboxed-containers/osc-monitor-rhel9, openshift-sandboxed-containers/osc-rhel9-operator, openshift-sandboxed-containers/osc-operator-bundle, openshift-sandboxed-containers/osc-podvm-builder-rhel9, openshift-sandboxed-containers/osc-podvm-payload-rhel9 Red Hat Multicluster Global Hub multicluster-globalhub/multicluster-globalhub-grafana-rhel9 Red Hat Network Observability Operator network-observability/network-observability-ebpf-agent-rhel9, network-observability/network-observability-flowlogs-pipeline-rhel9 Red Hat OpenShift Developer Tools and Services openshift4/ose-jenkins, ocp-tools-4/jenkins-rhel8, ocp-tools-4/jenkins-rhel9, ocp-tools-4/jenkins-agent-base-rhel8, ocp-tools-4/jenkins-agent-base-rhel9 Red Hat OpenShift Service Mesh 2 openshift-service-mesh/pilot-rhel8, openshift-service-mesh/proxyv2-rhel9, openshift-service-mesh/istio-cni-rhel8 Red Hat Advanced Cluster Management for Kubernetes 2 rhacm2/thanos-rhel9, rhacm2/prometheus-rhel9, rhacm2/acm-prometheus-rhel9, rhacm2/acm-prometheus-config-reloader-rhel9
    +6 more products
    Red Hat Enterprise Linux 8 runc, podman, podman-tests, podman-docker, podman-remote, podman-gvproxy, +3 more Red Hat Enterprise Linux 9 runc, podman, podman-tests, podman-docker, podman-remote, podman-gvproxy, +2 more Red Hat Enterprise Linux 10 delve Red Hat OpenShift Container Platform 4 runc, cri-o, podman, openshift, microshift, podman-tests, +56 more Red Hat OpenShift for Windows Containers openshift4-wincw/windows-machine-config-rhel9-operator, openshift4-wincw/windows-machine-config-operator-bundle Red Hat OpenShift Virtualization 4 kubevirt, container-native-virtualization/virt-api, container-native-virtualization/virt-handler, container-native-virtualization/virt-launcher, container-native-virtualization/virt-operator, container-native-virtualization/virt-api-rhel9, +17 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
8mo ago

Exploit prediction

0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 6.1 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
GitHub 3.1 6.1 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
NVD 3.1 5.4 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
OSV 3.1 5.4 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
go github.com/cilium/cilium
>=1.18.0, <1.18.6
1.18.6
bitnami cilium
>=1.18.0, <1.18.6
1.18.6
bitnami cilium-operator
>=1.18.0, <1.18.6
1.18.6
bitnami hubble-relay
>=1.18.0, <1.18.6
1.18.6

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.