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{"bugzilla": {"description": "Envoy: Envoy: De-synchronized CONNECT tunnel state due to early data handling in TCP proxy mode", "id": "2418664", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2418664"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.3", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N", "status": "draft"}, "cwe": "CWE-693", "details": ["Envoy is a high-performance edge/middle/service proxy. In 1.33.12, 1.34.10, 1.35.6, 1.36.2, and earlier, when Envoy is configured in TCP proxy mode to handle CONNECT requests, it accepts client data before issuing a 2xx response and forwards that data to the upstream TCP connection. If a forwarding proxy upstream from Envoy then responds with a non-2xx status, this can cause a de-synchronized CONNECT tunnel state. By default Envoy continues to allow early CONNECT data to avoid disrupting existing deployments. The envoy.reloadable_features.reject_early_connect_data runtime flag can be set to reject CONNECT requests that send data before a 2xx response when intermediaries upstream from Envoy may reject establishment of a CONNECT tunnel."], "mitigation": {"lang": "en:us", "value": "To mitigate this issue, set the `envoy.reloadable_features.reject_early_connect_data` runtime flag to reject CONNECT requests that send data before a 2xx response. This configuration change may require a service reload or restart to take effect."}, "name": "CVE-2025-64763", "package_state": [{"cpe": "cpe:/a:redhat:service_mesh:2", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh/grafana-rhel8", "product_name": "OpenShift Service Mesh 2"}, {"cpe": "cpe:/a:redhat:service_mesh:2", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh/istio-cni-rhel8", "product_name": "OpenShift Service Mesh 2"}, {"cpe": "cpe:/a:redhat:service_mesh:2", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh/istio-must-gather-rhel9", "product_name": "OpenShift Service Mesh 2"}, {"cpe": "cpe:/a:redhat:service_mesh:2", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh/istio-operator-bundle", "product_name": "OpenShift Service Mesh 2"}, {"cpe": "cpe:/a:redhat:service_mesh:2", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh/istio-rhel8-operator", "product_name": "OpenShift Service Mesh 2"}, {"cpe": "cpe:/a:redhat:service_mesh:2", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh/pilot-rhel8", "product_name": "OpenShift Service Mesh 2"}, {"cpe": "cpe:/a:redhat:service_mesh:2", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh/proxyv2-rhel9", "product_name": "OpenShift Service Mesh 2"}, {"cpe": "cpe:/a:redhat:service_mesh:2", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh/ratelimit-rhel8", "product_name": "OpenShift Service Mesh 2"}, {"cpe": "cpe:/a:redhat:service_mesh:3", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh-dev-preview-beta/istio-ztunnel-rhel9", "product_name": "OpenShift Service Mesh 3"}, {"cpe": "cpe:/a:redhat:service_mesh:3", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh/istio-cni-rhel9", "product_name": "OpenShift Service Mesh 3"}, {"cpe": "cpe:/a:redhat:service_mesh:3", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh/istio-must-gather-rhel9", "product_name": "OpenShift Service Mesh 3"}, {"cpe": "cpe:/a:redhat:service_mesh:3", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh/istio-pilot-rhel9", "product_name": "OpenShift Service Mesh 3"}, {"cpe": "cpe:/a:redhat:service_mesh:3", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh/istio-proxyv2-rhel9", "product_name": "OpenShift Service Mesh 3"}, {"cpe": "cpe:/a:redhat:service_mesh:3", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh/istio-rhel9-operator", "product_name": "OpenShift Service Mesh 3"}, {"cpe": "cpe:/a:redhat:service_mesh:3", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh/istio-sail-operator-bundle", "product_name": "OpenShift Service Mesh 3"}, {"cpe": "cpe:/a:redhat:service_mesh:3", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh/istio-ztunnel-rhel9", "product_name": "OpenShift Service Mesh 3"}, {"cpe": "cpe:/a:redhat:service_mesh:3", "fix_state": "Fix deferred", "package_name": "openshift-service-mesh-tech-preview/istio-ztunnel-rhel9", "product_name": "OpenShift Service Mesh 3"}], "public_date": "2025-12-03T18:13:58Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2025-64763\nhttps://nvd.nist.gov/vuln/detail/CVE-2025-64763\nhttps://github.com/envoyproxy/envoy/security/advisories/GHSA-rj35-4m94-77jh"], "statement": "This vulnerability is rated Moderate for Red Hat. Envoy, when operating in TCP proxy mode for CONNECT requests, forwards client data before a 2xx response. This can lead to a de-synchronized CONNECT tunnel state if an upstream proxy rejects the tunnel establishment. This behavior is enabled by default in affected versions of OpenShift Service Mesh.", "threat_severity": "Moderate"}

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