CVE-2023-39347 Cilium NetworkPolicy bypass via pod labels

What is CVE-2023-39347?

CVE-2023-39347 is a high-severity vulnerability in cilium, published on 26 Sep 2023. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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.

Weakness: CWE-345

Which versions are affected by CVE-2023-39347?

14 open source packages ship an affected version, including github.com/cilium/cilium, cilium and cilium-operator. It affects 1 product.

Products include Cilium Cilium.

How do I fix CVE-2023-39347?

Upgrade github.com/cilium/cilium to a fixed version for your release line: 1.12.14, 1.13.7 or 1.14.2.

Is CVE-2023-39347 being exploited?

There is no known exploitation of CVE-2023-39347 in the wild and no public exploit code.

Other vulnerabilities in cilium

• CVE-2026-49445 Cilium: Sensitive information disclosure and cluster disruption via local Envoy admin socket access Critical 9.2
• CVE-2022-29178 Incorrect Default Permissions in Cilium High 8.8
• CVE-2024-28860 Insecure IPsec transport encryption in Cilium High 8.0
• CVE-2026-41520 Cillium exposes sensitive information included in the cilium-bugtool debug archive High 7.9
• CVE-2024-37307 Cilium leaks sensitive information in cilium-bugtool High 7.9

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as 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 and 3 more.