CVE-2023-39347

Network policy bypass via trusted pod labels

Published Sep 26, 2023 · Updated Sep 24, 2024

Network policy bypass in Cilium before 1.12.14, 1.13.0 through 1.13.6, and 1.14.0 through 1.14.1 allows attackers to evade traffic controls. During pod updates, the agent trusts user-supplied namespace, service-account, and cluster identity labels when selecting applicable policies, so nonexistent construct names leave the pod unmatched. Exploitation requires Kubernetes API credentials that permit pod-label updates, and the resulting bypass exposes traffic that those network policies were meant to restrict.

CVSS severity5.4
Medium
EPSS probability0.50%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Network policy bypass in Cilium before 1.12.14, 1.13.0 through 1.13.6, and 1.14.0 through 1.14.1 allows attackers to evade traffic controls. During pod updates, the agent trusts user-supplied namespace, service-account, and cluster identity labels when selecting applicable policies, so nonexistent construct names leave the pod unmatched. Exploitation requires Kubernetes API credentials that permit pod-label updates, and the resulting bypass exposes traffic that those network policies were meant to restrict.

The record

CVE
CVE-2023-39347
Published
Sep 26, 2023
Updated
Sep 24, 2024
Vendor
Cilium
Product
Cilium
Classifications
CWE-345, T1562.004
Attack vector
adjacent
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 26, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 24, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.12.14
  2. Affected versionversion=>= 1.13.0, < 1.13.7
  3. Affected versionversion=>= 1.14.0, < 1.14.2

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesauthenticated

What is affected?

Cilium · Ciliumversion=< 1.12.14; version=>= 1.13.0, < 1.13.7; version=>= 1.14.0, < 1.14.2

Published CVSS scores

9.0NIST NVDCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
5.4GitHub, Inc.CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-345Insufficient Verification of Data Authenticity
T1562.004Disable or Modify System Firewall

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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