{"id":"CVE-2026-56742","aliases":["BIT-cilium-2026-56742","BIT-cilium-operator-2026-56742","BIT-hubble-relay-2026-56742","GHSA-w7c2-w76w-5hmj","GO-2026-6596"],"url":"https://o3.security/vulnerability/CVE-2026-56742","summary":"Cilium: Namespaced HTTPRoutes can redirect traffic to other namespaces","details":"### Impact\n\nIn Cilium clusters using [Gateway API](https://docs.cilium.io/en/stable/network/servicemesh/gateway-api/gateway-api/), users with permissions to create or update namespaced HTTPRoutes can mirror HTTP traffic to any Service in any namespace, bypassing the ReferenceGrant authorization mechanism.\n\nGateway API functionality is disabled by default.\n\n### Patches\n\nThis issue affects:\n\n* Cilium v1.19 from v1.19.0 to v1.19.4 inclusive\n* Cilium v1.18 from v1.18.0 to v1.18.10 inclusive\n* All versions of Cilium before v1.17.17\n\nThis issue is patched in:\n\n* Cilium v1.19.5\n* Cilium v1.18.11\n* Cilium v1.17.17\n\n### Workarounds\n\nThere is no workaround to this issue. Users of this feature who are unable to upgrade can mitigate the risk by ensuring that RBAC permissions to create `HTTPRoute` objects are only granted to cluster admins.\n\n### Acknowledgements\n\nThe Cilium community has worked together with members of Isovalent to prepare these mitigations. Special thanks to @galanko for reporting the issue and @mhofstetter for their work on triaging and remediating this 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/).\n\nIf you think you have found a vulnerability affecting Cilium, we strongly encourage you to report it to our security mailing list at [security@cilium.io](mailto:security@cilium.io). This is a private mailing list for the Cilium security team, and your report will be treated as top priority.","published":"2026-07-15T19:14:07.617Z","modified":"2026-10-21T02:30:35.155368916Z","cvss":{"score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:L/I:L/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/cilium/cilium","fixedVersion":"1.17.17"},{"ecosystem":"Go","name":"github.com/cilium/ciliumCilium","fixedVersion":"1.18.11"},{"ecosystem":"Go","name":"github.com/cilium/cilium","fixedVersion":"1.19.5"}],"fix":{"url":"https://github.com/cilium/cilium/commit/7422068aff67ac77c7dcc57aa5b9240c91333deb","label":"cilium/cilium@7422068"},"references":[{"type":"WEB","url":"https://github.com/cilium/cilium/releases/tag/v1.17.17"},{"type":"WEB","url":"https://github.com/cilium/cilium/releases/tag/v1.18.11"},{"type":"WEB","url":"https://github.com/cilium/cilium/releases/tag/v1.19.5"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/56xxx/CVE-2026-56742.json"},{"type":"ADVISORY","url":"https://github.com/cilium/cilium/security/advisories/GHSA-w7c2-w76w-5hmj"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-56742"},{"type":"FIX","url":"https://github.com/cilium/cilium/commit/7422068aff67ac77c7dcc57aa5b9240c91333deb"},{"type":"FIX","url":"https://github.com/cilium/cilium/commit/e0b1cef513ff910323f3743e9f3e3d86721e4857"},{"type":"FIX","url":"https://github.com/cilium/cilium/commit/f23929cff682d6ed0dc158070812cb302fc0032b"},{"type":"FIX","url":"https://github.com/cilium/cilium/commit/fd47963ea394d5e8fa4a88c40a79063430c512ca"},{"type":"PACKAGE","url":"https://github.com/cilium/cilium"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-21T02:30:35.155368916Z"}}