{"id":"CVE-2026-56743","aliases":["BIT-cilium-2026-56743","BIT-cilium-operator-2026-56743","BIT-hubble-relay-2026-56743","GHSA-fm8w-2m5w-9j7r"],"url":"https://o3.security/vulnerability/CVE-2026-56743","summary":"Cilium may unexpectedly allow ingress traffic from the local namespace when a Kubernetes NetworkPolicy is configured with an ipBlock match","details":"Cilium is a networking, observability, and security solution. From 1.19.0 to 1.19.4, standard Kubernetes NetworkPolicy specifications using CIDR-based ipBlock rules without pod or namespace selectors erroneously generate a wildcard namespace allow rule when Cilium is configured with a custom clusterName rather than the default any value. The parser incorrectly instantiates a pod selector on selectorless peer definitions, allowing traffic from other workloads in the same namespace as the subject of the policy. This issue is fixed in version 1.19.5.","published":"2026-07-15T19:15:30.924Z","modified":"2026-08-12T03:51:25.338592309Z","cvss":{"score":5.4,"severity":"MEDIUM","vector":"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/cilium/cilium","fixedVersion":"1.19.5"}],"fix":{"url":"https://github.com/cilium/cilium/commit/1c84ae3b58a7cd54f7ee355e6c524c82f620eae8","label":"cilium/cilium@1c84ae3"},"references":[{"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-2026-56743.json"},{"type":"ADVISORY","url":"https://github.com/cilium/cilium/security/advisories/GHSA-fm8w-2m5w-9j7r"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-56743"},{"type":"FIX","url":"https://github.com/cilium/cilium/commit/1c84ae3b58a7cd54f7ee355e6c524c82f620eae8"},{"type":"FIX","url":"https://github.com/cilium/cilium/commit/bacea640404c0805c23515353dc1681c5bf35171"},{"type":"FIX","url":"https://github.com/cilium/cilium/pull/46305"},{"type":"FIX","url":"https://github.com/cilium/cilium/pull/46456"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:25.338592309Z"}}