{"id":"CVE-2026-56743","state":"PUBLISHED","title":"Cilium may unexpectedly allow ingress traffic from the local namespace when a Kubernetes NetworkPolicy is configured with an ipBlock match","description":"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.","publishedAt":"2026-07-15T19:15:30.924Z","updatedAt":"2026-07-16T13:03:36.080Z","severity":{"score":5.4,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["cilium cilium"],"affected":[{"vendor":"cilium","product":"cilium","versions":[{"version":">= 1.19.0, < 1.19.5","status":"affected"}]}],"references":["https://github.com/cilium/cilium/security/advisories/GHSA-fm8w-2m5w-9j7r","https://github.com/cilium/cilium/pull/46305","https://github.com/cilium/cilium/pull/46456","https://github.com/cilium/cilium/commit/1c84ae3b58a7cd54f7ee355e6c524c82f620eae8","https://github.com/cilium/cilium/commit/bacea640404c0805c23515353dc1681c5bf35171","https://github.com/cilium/cilium/releases/tag/v1.19.5"],"weaknesses":["CWE-863"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/56xxx/CVE-2026-56743.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-56743","state":"PUBLISHED","datePublished":"2026-07-15T19:15:30.924Z","dateUpdated":"2026-07-16T13:03:36.080Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-22T19:17:28.959Z"},"containers":{"cna":{"title":"Cilium may unexpectedly allow ingress traffic from the local namespace when a Kubernetes NetworkPolicy is configured with an ipBlock match","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"cilium","product":"cilium","versions":[{"version":">= 1.19.0, < 1.19.5","status":"affected"}]}],"references":[{"url":"https://github.com/cilium/cilium/security/advisories/GHSA-fm8w-2m5w-9j7r","name":"https://github.com/cilium/cilium/security/advisories/GHSA-fm8w-2m5w-9j7r","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/cilium/cilium/pull/46305","name":"https://github.com/cilium/cilium/pull/46305","tags":["x_refsource_MISC"]},{"url":"https://github.com/cilium/cilium/pull/46456","name":"https://github.com/cilium/cilium/pull/46456","tags":["x_refsource_MISC"]},{"url":"https://github.com/cilium/cilium/commit/1c84ae3b58a7cd54f7ee355e6c524c82f620eae8","name":"https://github.com/cilium/cilium/commit/1c84ae3b58a7cd54f7ee355e6c524c82f620eae8","tags":["x_refsource_MISC"]},{"url":"https://github.com/cilium/cilium/commit/bacea640404c0805c23515353dc1681c5bf35171","name":"https://github.com/cilium/cilium/commit/bacea640404c0805c23515353dc1681c5bf35171","tags":["x_refsource_MISC"]},{"url":"https://github.com/cilium/cilium/releases/tag/v1.19.5","name":"https://github.com/cilium/cilium/releases/tag/v1.19.5","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"ADJACENT_NETWORK","availabilityImpact":"NONE","baseScore":5.4,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"LOW","scope":"CHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-863","lang":"en","description":"CWE-863: Incorrect Authorization","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-15T19:15:30.924Z"},"source":{"advisory":"GHSA-fm8w-2m5w-9j7r","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-16T13:02:42.889041Z","id":"CVE-2026-56743","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-16T13:03:36.080Z"}}]}}}