{"id":"CVE-2023-27594","aliases":["BIT-cilium-2023-27594","BIT-cilium-operator-2023-27594","BIT-cilium-proxy-2023-27594","BIT-hubble-2023-27594","BIT-hubble-relay-2023-27594","BIT-hubble-ui-2023-27594","BIT-hubble-ui-backend-2023-27594","GHSA-8fg8-jh2h-f2hc","GO-2023-1643"],"url":"https://o3.security/vulnerability/CVE-2023-27594","summary":"Cilium vulnerable to potential network policy bypass when routing IPv6 traffic ","details":"## Impact\n\nUnder specific conditions, Cilium may misattribute the source IP address of traffic to a cluster, identifying external traffic as coming from the host on which Cilium is running. As a consequence, network policies for that cluster might be bypassed, depending on the specific network policies enabled. Only IPv6 traffic is impacted by this vulnerability.\n\nThis issue only manifests when:\n* Cilium is routing IPv6 traffic, and\n* Kube-proxy is used for service handling, and\n* NodePorts are used to route traffic to pods.\n\nIPv6 is disabled by default. Cilium's kube-proxy replacement feature is not affected by this vulnerability.\n\n## Patches\n\nThe problem has been fixed and is available on versions >=1.11.15, >=1.12.8, >=1.13.1\n\n## Workarounds\n\nDisable IPv6 routing (IPv6 is disabled by default).\n\n## Acknowledgements\n\nThe Cilium community has worked together with members of Isovalent to prepare these mitigations. Special thanks to Yusuke Suzuki for both highlighting and fixing the issue.\n\n## For more information\n\nIf you have any questions or comments about this advisory, please reach out on [Slack](https://docs.cilium.io/en/latest/community/community/#slack).\n\nAs usual, if you think you found a related vulnerability, we strongly encourage you to report security vulnerabilities to our private security mailing list: security@cilium.io - first, before disclosing them in any public forums. This is a private mailing list where only members of the Cilium internal security team are subscribed to, and is treated as top priority.","published":"2023-03-17T19:56:43.687Z","modified":"2026-08-12T03:51:48.987741780Z","cvss":{"score":4.2,"severity":"MEDIUM","vector":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N"},"epss":{"score":0.00552,"percentile":0.44844,"asOf":"2026-09-17"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/cilium/cilium","fixedVersion":"1.11.15"},{"ecosystem":"Go","name":"github.com/cilium/cilium","fixedVersion":"1.12.8"},{"ecosystem":"Go","name":"github.com/cilium/cilium","fixedVersion":"1.13.1"}],"fix":null,"references":[{"type":"WEB","url":"https://github.com/cilium/cilium/releases/tag/v1.11.15"},{"type":"WEB","url":"https://github.com/cilium/cilium/releases/tag/v1.12.8"},{"type":"WEB","url":"https://github.com/cilium/cilium/releases/tag/v1.13.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/27xxx/CVE-2023-27594.json"},{"type":"ADVISORY","url":"https://github.com/cilium/cilium/security/advisories/GHSA-8fg8-jh2h-f2hc"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-27594"},{"type":"PACKAGE","url":"https://github.com/cilium/cilium"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:48.987741780Z"}}