CVE-2026-33726

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-33726", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-03-23T17:34:57.559Z", "datePublished": "2026-03-27T00:23:21.795Z", "dateUpdated": "2026-03-27T13:50:24.672Z"}, "containers": {"cna": {"title": "Cilium L7 proxy may bypass Kubernetes NetworkPolicy for same-node traffic", "problemTypes": [{"descriptions": [{"cweId": "CWE-284", "lang": "en", "description": "CWE-284: Improper Access Control", "type": "CWE"}]}, {"descriptions": [{"cweId": "CWE-863", "lang": "en", "description": "CWE-863: Incorrect Authorization", "type": "CWE"}]}], "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"}}], "references": [{"name": "https://github.com/cilium/cilium/security/advisories/GHSA-hxv8-4j4r-cqgv", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/cilium/cilium/security/advisories/GHSA-hxv8-4j4r-cqgv"}, {"name": "https://github.com/cilium/cilium/pull/44693", "tags": ["x_refsource_MISC"], "url": "https://github.com/cilium/cilium/pull/44693"}, {"name": "https://docs.cilium.io/en/stable/network/concepts/routing/#routing", "tags": ["x_refsource_MISC"], "url": "https://docs.cilium.io/en/stable/network/concepts/routing/#routing"}, {"name": "https://docs.cilium.io/en/stable/network/kubernetes/policy/#network-policy", "tags": ["x_refsource_MISC"], "url": "https://docs.cilium.io/en/stable/network/kubernetes/policy/#network-policy"}, {"name": "https://docs.cilium.io/en/stable/network/servicemesh/l7-traffic-management", "tags": ["x_refsource_MISC"], "url": "https://docs.cilium.io/en/stable/network/servicemesh/l7-traffic-management"}, {"name": "https://docs.cilium.io/en/stable/operations/performance/tuning/#ebpf-host-routing", "tags": ["x_refsource_MISC"], "url": "https://docs.cilium.io/en/stable/operations/performance/tuning/#ebpf-host-routing"}], "affected": [{"vendor": "cilium", "product": "cilium", "versions": [{"version": "< 1.17.14", "status": "affected"}, {"version": ">= 1.18.0, < 1.18.8", "status": "affected"}, {"version": ">= 1.19.0, < 1.19.2", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-03-27T00:23:21.795Z"}, "descriptions": [{"lang": "en", "value": "Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Prior to versions 1.17.14, 1.18.8, and 1.19.2, Ingress Network Policies are not enforced for traffic from pods to L7 Services (Envoy, GAMMA) with a local backend on the same node, when Per-Endpoint Routing is enabled and BPF Host Routing is disabled. Per-Endpoint Routing is disabled by default, but is automatically enabled in deployments using cloud IPAM, including Cilium ENI on EKS (`eni.enabled`), AlibabaCloud ENI (`alibabacloud.enabled`), Azure IPAM (`azure.enabled`, but not AKS BYOCNI), and some GKE deployments (`gke.enabled`; managed offerings such as GKE Dataplane V2 may use different defaults). It is typically not enabled in tunneled deployments, and chaining deployments are not affected. In practice, Amazon EKS with Cilium ENI mode is likely the most common affected environment. Versions 1.17.14, 1.18.8, and 1.19.2 contain a patch. There is currently no officially verified or comprehensive workaround for this issue. The only option would be to disable per-endpoint routes, but this will likely cause disruptions to ongoing connections, and potential conflicts if running in cloud providers."}], "source": {"advisory": "GHSA-hxv8-4j4r-cqgv", "discovery": "UNKNOWN"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-03-27T13:24:20.808024Z", "id": "CVE-2026-33726", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-03-27T13:50:24.672Z"}}]}}

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{"affected": [{"affectedData": [{"product": "cilium", "vendor": "cilium", "versions": [{"status": "affected", "version": "< 1.17.14"}, {"status": "affected", "version": ">= 1.18.0, < 1.18.8"}, {"status": "affected", "version": ">= 1.19.0, < 1.19.2"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:cilium:cilium:*:*:*:*:*:*:*:*", "matchCriteriaId": "1544DC73-F250-4536-B6EB-DADBA95C83EC", "versionEndExcluding": "1.17.14", "vulnerable": true}, {"criteria": "cpe:2.3:a:cilium:cilium:*:*:*:*:*:*:*:*", "matchCriteriaId": "7695E23A-4AF0-44E0-8282-0E4435451C9C", "versionEndExcluding": "1.18.8", "versionStartIncluding": "1.18.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:cilium:cilium:*:*:*:*:*:*:*:*", "matchCriteriaId": "3D2F4891-29A2-4B8F-BE6E-900EB5DDCC0A", "versionEndExcluding": "1.19.2", "versionStartIncluding": "1.19.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Cilium is a networking, observability, and security solution with an eBPF-based dataplane. Prior to versions 1.17.14, 1.18.8, and 1.19.2, Ingress Network Policies are not enforced for traffic from pods to L7 Services (Envoy, GAMMA) with a local backend on the same node, when Per-Endpoint Routing is enabled and BPF Host Routing is disabled. Per-Endpoint Routing is disabled by default, but is automatically enabled in deployments using cloud IPAM, including Cilium ENI on EKS (`eni.enabled`), AlibabaCloud ENI (`alibabacloud.enabled`), Azure IPAM (`azure.enabled`, but not AKS BYOCNI), and some GKE deployments (`gke.enabled`; managed offerings such as GKE Dataplane V2 may use different defaults). It is typically not enabled in tunneled deployments, and chaining deployments are not affected. In practice, Amazon EKS with Cilium ENI mode is likely the most common affected environment. Versions 1.17.14, 1.18.8, and 1.19.2 contain a patch. There is currently no officially verified or comprehensive workaround for this issue. The only option would be to disable per-endpoint routes, but this will likely cause disruptions to ongoing connections, and potential conflicts if running in cloud providers."}, {"lang": "es", "value": "Cilium es una soluci\u00f3n de red, observabilidad y seguridad con un plano de datos basado en eBPF. Antes de las versiones 1.17.14, 1.18.8 y 1.19.2, las pol\u00edticas de red de entrada (Ingress Network Policies) no se aplican para el tr\u00e1fico de pods a servicios L7 (Envoy, GAMMA) con un backend local en el mismo nodo, cuando el enrutamiento por punto final (Per-Endpoint Routing) est\u00e1 habilitado y el enrutamiento de host BPF (BPF Host Routing) est\u00e1 deshabilitado. El enrutamiento por punto final (Per-Endpoint Routing) est\u00e1 deshabilitado por defecto, pero se habilita autom\u00e1ticamente en implementaciones que utilizan IPAM en la nube, incluyendo Cilium ENI en EKS ('eni.enabled'), AlibabaCloud ENI ('alibabacloud.enabled'), Azure IPAM ('azure.enabled', pero no AKS BYOCNI), y algunas implementaciones de GKE ('gke.enabled'; las ofertas gestionadas como GKE Dataplane V2 pueden usar valores predeterminados diferentes). Normalmente no est\u00e1 habilitado en implementaciones con t\u00faneles, y las implementaciones en cadena no se ven afectadas. En la pr\u00e1ctica, Amazon EKS con modo Cilium ENI es probablemente el entorno afectado m\u00e1s com\u00fan. Las versiones 1.17.14, 1.18.8 y 1.19.2 contienen un parche. Actualmente no existe una soluci\u00f3n alternativa oficialmente verificada o completa para este problema. La \u00fanica opci\u00f3n ser\u00eda deshabilitar las rutas por punto final, pero esto probablemente causar\u00e1 interrupciones en las conexiones en curso, y posibles conflictos si se ejecuta en proveedores de la nube."}], "id": "CVE-2026-33726", "lastModified": "2026-06-17T10:37:59.757", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 2.3, "impactScore": 2.7, "source": "security-advisories@github.com", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "ADJACENT_NETWORK", "availabilityImpact": "NONE", "baseScore": 4.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 1.4, "source": "nvd@nist.gov", "type": "Primary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-33726", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-03-27T13:24:20.808024Z", "version": "2.0.3"}}]}, "published": "2026-03-27T01:16:20.007", "references": [{"source": "security-advisories@github.com", "tags": ["Technical Description"], "url": "https://docs.cilium.io/en/stable/network/concepts/routing/#routing"}, {"source": "security-advisories@github.com", "tags": ["Technical Description"], "url": "https://docs.cilium.io/en/stable/network/kubernetes/policy/#network-policy"}, {"source": "security-advisories@github.com", "tags": ["Technical Description"], "url": "https://docs.cilium.io/en/stable/network/servicemesh/l7-traffic-management"}, {"source": "security-advisories@github.com", "tags": ["Technical Description"], "url": "https://docs.cilium.io/en/stable/operations/performance/tuning/#ebpf-host-routing"}, {"source": "security-advisories@github.com", "tags": ["Issue Tracking", "Patch"], "url": "https://github.com/cilium/cilium/pull/44693"}, {"source": "security-advisories@github.com", "tags": ["Patch", "Vendor Advisory"], "url": "https://github.com/cilium/cilium/security/advisories/GHSA-hxv8-4j4r-cqgv"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-284"}, {"lang": "en", "value": "CWE-863"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,1.17.14)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[1.18.0,1.18.8)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[1.19.0,1.19.2)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "cilium", "source": "cna", "vendor": "cilium"}, "product": "cilium", "vendor": "cilium"}], "analysis": {"en": {"generated_at": "2026-04-02T04:12:42.180855+00:00", "value": {"mitigation_remediation": ["Update Cilium to version 1.17.14, 1.18.8, 1.19.2 or later.", "If immediate remediation is required, disable Per\u2011Endpoint Routing, noting that this may interrupt existing connections.", "Verify that BPF Host Routing is appropriately disabled or configured.", "Test NetworkPolicy enforcement by sending test traffic between pods and L7 services.", "Keep the Kubernetes cluster and Cilium components up to date to prevent future similar weaknesses."], "summary": {"action": "Patch", "impact": "Bypass of Kubernetes NetworkPolicy for same-node traffic"}, "threat_synthesis": {"affected_systems": "The vulnerability affects Cilium versions prior to 1.17.14, 1.18.8, and 1.19.2. It is relevant for deployments that use cloud IPAM, including Cilium ENI on Amazon EKS, AlibabaCloud ENI, Azure IPAM (except AKS BYOCNI), and certain GKE setups. Typical affected environments are EKS with Cilium ENI mode; tunneled or chaining deployments and GKE Dataplane\u00a0V2 managed offerings are not impacted.", "description_and_impact": "Cilium\u2019s L7 proxy can allow traffic from a pod to a locally back\u2011ended L7 Service to skip enforced ingress NetworkPolicies when Per\u2011Endpoint Routing is enabled and BPF Host Routing is disabled. This creates an unauthorized data path between the pod and the service, enabling an attacker to send traffic that normally would be denied by cluster policy, potentially compromising confidentiality and integrity. The flaw stems from improper access control and a privilege\u2011check bypass.", "risk_and_exploitability": "The CVSS score is 5.4 and the EPSS score is below 1\u202f%, indicating moderate severity and low expected exploitation likelihood. The issue is not listed in CISA\u2019s KEV catalog. The attack vector relies on local\u2011node pod traffic\u2014an attacker needs a pod on the same node as the target service to exploit the bypass. Updating to the patched version mitigates the flaw, while disabling Per\u2011Endpoint Routing can act as a temporary workaround at the cost of potential connection disruptions."}}}}, "created": "2026-03-27T08:31:12.526838+00:00", "updated": "2026-04-02T07:55:53.980882+00:00", "vendors": ["cilium", "cilium$PRODUCT$cilium"]}