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Fencer Vulns
high 7.6

CVE-2023-39347 json

Cilium NetworkPolicy bypass via pod labels

published 2023-09-26 3 y ago modified 2026-09-10 1 mo ago also BIT-cilium-2023-39347 , BIT-cilium-operator-2023-39347 , BIT-cilium-proxy-2023-39347 , BIT-hubble-2023-39347 , BIT-hubble-relay-2023-39347 , BIT-hubble-ui-2023-39347 , BIT-hubble-ui-backend-2023-39347 , EUVD-2023-2509 , GHSA-gj2r-phwg-6rww , GO-2023-2078

cvss
7.6
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

Cilium is a networking, observability, and security solution with an eBPF-based dataplane. An attacker with the ability to update pod labels can cause Cilium to apply incorrect network policies. This issue arises due to the fact that on pod update, Cilium incorrectly uses user-provided pod labels to select the policies which apply to the workload in question. This can affect Cilium network policies that use the namespace, service account or cluster constructs to restrict traffic, Cilium clusterwide network policies that use Cilium namespace labels to select the Pod and Kubernetes network policies. Non-existent construct names can be provided, which bypass all network policies applicable to the construct. For example, providing a pod with a non-existent namespace as the value of the `io.kubernetes.pod.namespace` label results in none of the namespaced CiliumNetworkPolicies applying to the pod in question. This attack requires the attacker to have Kubernetes API Server access, as described in the Cilium Threat Model. This issue has been resolved in: Cilium versions 1.14.2, 1.13.7, and 1.12.14. Users are advised to upgrade. As a workaround an admission webhook can be used to prevent pod label updates to the `k8s:io.kubernetes.pod.namespace` and `io.cilium.k8s.policy.*` keys.

Patch / fix

  • go github.com/cilium/cilium 1.12.14, 1.13.7, 1.14.2
  • bitnami cilium 1.12.14, 1.13.7, 1.14.2
  • bitnami cilium-operator 1.12.14, 1.13.7, 1.14.2
  • bitnami cilium-proxy 1.12.14, 1.13.7, 1.14.2
  • bitnami hubble 1.12.14, 1.13.7, 1.14.2
  • bitnami hubble-relay 1.12.14, 1.13.7, 1.14.2
  • bitnami hubble-ui 1.12.14, 1.13.7, 1.14.2
  • bitnami hubble-ui-backend 1.12.14, 1.13.7, 1.14.2
  • cilium cilium 1.12.14, 1.13.7, 1.14.2

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.57% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • docs.cilium.io https://docs.cilium.io/en/latest/security/threat-model/#kubernetes-api-server-attacker referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.6 CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:H
GitHub 3.1 5.4 CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:L
NVD 3.1 9.0 CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
OSV 3.1 9.0 CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
go github.com/cilium/cilium
>=1.13.0, <1.13.7
>=1.14.0, <1.14.2
<1.12.14
1.13.7
1.14.2
1.12.14
bitnami cilium
<1.12.14
>=1.13.0, <1.13.7
>=1.14.0, <1.14.2
1.12.14
1.13.7
1.14.2
bitnami cilium-operator
<1.12.14
>=1.13.0, <1.13.7
>=1.14.0, <1.14.2
1.12.14
1.13.7
1.14.2
bitnami cilium-proxy
<1.12.14
>=1.13.0, <1.13.7
>=1.14.0, <1.14.2
1.12.14
1.13.7
1.14.2
bitnami hubble
<1.12.14
>=1.13.0, <1.13.7
>=1.14.0, <1.14.2
1.12.14
1.13.7
1.14.2
bitnami hubble-relay
<1.12.14
>=1.13.0, <1.13.7
>=1.14.0, <1.14.2
1.12.14
1.13.7
1.14.2
bitnami hubble-ui
<1.12.14
>=1.13.0, <1.13.7
>=1.14.0, <1.14.2
1.12.14
1.13.7
1.14.2
bitnami hubble-ui-backend
<1.12.14
>=1.13.0, <1.13.7
>=1.14.0, <1.14.2
1.12.14
1.13.7
1.14.2

Affected products

  • cilium cilium

Classification

Weakness
  • CWE-345 Insufficient Verification of Data Authenticity

References

Sources

Fencer Vulns 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.