CVE-2023-39347

What it is

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.

At a glance

Exploitability

Can be exploited from the same network segment with a low-privilege account. High risk of service disruption.

Exploit odds

0.6% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2023-09-27 15:18 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 06:12 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.6% in the next 30 days (EPSS).
• Severity: 7.6 HIGH (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2023-09-27 15:18 UTC

Last modified

2026-06-17 06:12 UTC

Exploit probability

0.6% · EPSS, next 30 days

Weakness

CWE-345

Record status

Modified

Affected

• Cilium < 1.12.14
• Cilium < 1.13.7
• Cilium < 1.14.2

Attack profile CVSS 3.1 · 7.6

Attack vector

Adjacent network

Complexity

Low

Privileges needed

Low

User interaction

None

Scope

Changed

Confidentiality

Low

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2023-39347.md and follow it. Check whether this project is affected by CVE-2023-39347. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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