CVE-2023-39347: Kubernetes users may update Pod labels to bypass network policy in github.com/cilium/cilium
Summary
CVE-2023-39347: Kubernetes users may update Pod labels to bypass network policy. Affects github.com/cilium/cilium across 3 version ranges.
< 1.12.14
>= 1.13.0, < 1.13.7
>= 1.14.0, < 1.14.2
Fixed in 1.12.14, 1.13.7 or 1.14.2, depending on the release line you run. How to fix ↓
Also tracked for
- hubble-ui · Bitnami
- hubble-ui-backend · Bitnami
- cilium-proxy · Bitnami
- hubble · Bitnami
- hubble-relay · Bitnami
- cilium · Bitnami
- cilium-operator · Bitnami
The same CVE-2023-39347 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
github.com/cilium/cilium is an open-source project written in Go that provides networking and security services for Kubernetes. It is used to enforce network policies and secure communication between pods in a Kubernetes cluster.
Vulnerability Detail
An attacker with the ability to update pod labels can cause Cilium to apply incorrect network policies. This vulnerability allows the attacker to bypass network policies that restrict traffic based on namespace, service account, or cluster constructs. By providing non-existent construct names as pod labels, the attacker can bypass all network policies applicable to the construct. This attack requires the attacker to have Kubernetes API Server access.
How To Fix
Latest published version: v1.20.3 as of 22 Oct 2026
go get github.com/cilium/cilium@v1.20.3Upgrading to it may include breaking changes; the versions below are the minimum fixed release for this vulnerability.
If you can't move to the latest
The minimum fixed version depends on the release line you run.
-
< 1.12.141.12.14go get github.com/cilium/cilium@v1.12.14 -
>= 1.13.0, < 1.13.71.13.7go get github.com/cilium/cilium@v1.13.7 -
>= 1.14.0, < 1.14.21.14.2go get github.com/cilium/cilium@v1.14.2
Tip — Not sure which release line you're on? Vulert can find the fix for the version you are using. Scan free →
Workaround
A temporary workaround is to use an admission webhook to prevent pod label updates to the k8s:io.kubernetes.pod.namespace and io.cilium.k8s.policy.* keys.
Conclusion
The vulnerability in github.com/cilium/cilium allows attackers to bypass network policies in Kubernetes clusters. Users should upgrade to the latest version of Cilium to fix this vulnerability. In the meantime, an admission webhook can be used as a temporary workaround. For further support on vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for github.com/cilium/cilium →
FAQ
The vulnerability allows an attacker to bypass network policies and potentially gain unauthorized access to resources within the Kubernetes cluster.
Users of Cilium versions <= v1.14.1, <= v1.13.6, and <= v1.12.13 are affected by this vulnerability.
You can use Vulert's playground (https://vulert.com/scanner) to check if your application is affected by this vulnerability. Vulert monitors and alerts in real-time for open-source vulnerabilities without requiring access to the code or installation.
Yes, upgrading to the latest version of Cilium (v1.14.2, v1.13.7, or v1.12.14) resolves this vulnerability. Additionally, using an admission webhook to prevent pod label updates can serve as a temporary workaround.
For more information, you can refer to the Cilium community's Slack channel or reach out to the Cilium security team via email at security@cilium.io.
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