CVE-2023-27594Network attack vector

Network policy bypass via IPv6 source misattribution

Published Mar 17, 2023 · Updated Feb 25, 2025

Improper authorization in Cilium before 1.11.15, 1.12.0 through 1.12.7, and 1.13.0 allows remote attackers to bypass network policies. The IPv6 NodePort path assigns external packets the host source identity, causing policy evaluation to trust traffic that originated outside the node. Exposure requires IPv6 routing, kube-proxy service handling, NodePorts, and matching policies; IPv6 is disabled by default.

CVSS severity4.2
Medium
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authorization in Cilium before 1.11.15, 1.12.0 through 1.12.7, and 1.13.0 allows remote attackers to bypass network policies. The IPv6 NodePort path assigns external packets the host source identity, causing policy evaluation to trust traffic that originated outside the node. Exposure requires IPv6 routing, kube-proxy service handling, NodePorts, and matching policies; IPv6 is disabled by default.

The record

CVE
CVE-2023-27594
Published
Mar 17, 2023
Updated
Feb 25, 2025
Vendor
Cilium
Product
Cilium
Classifications
CWE-285, CWE-863, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 17, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 2025Record 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=< 1.11.15
  2. Affected versionversion=>= 1.12.0, < 1.12.8
  3. Affected versionversion=>= 1.13.0, < 1.13.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Cilium · Ciliumversion=< 1.11.15; version=>= 1.12.0, < 1.12.8; version=>= 1.13.0, < 1.13.1

Published CVSS scores

4.2GitHub, Inc.CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
7.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
5.4Cilium GitHub Security AdvisoryCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-285Improper Authorization
CWE-863Incorrect Authorization
T1190Exploit Public-Facing Application

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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