{"cve":"CVE-2026-53718","nvd":{"published":"2026-09-14T21:17:13.140","modified":"2026-09-25T14:10:13.927","status":"Awaiting Analysis","description":"Envoy Gateway is an open source project for managing Envoy Proxy as a standalone or Kubernetes-based application gateway. Prior to 1.7.4 and 1.8.1, an HTTPRoute can use an extension-managed custom backendRef to reference a backend resource in another namespace without a matching Gateway API ReferenceGrant in the target namespace. The custom-backend branch in internal/gatewayapi/route.go omits validateBackendNamespace, allowing the route-owning namespace to bind to and use the resource without the backend namespace owner's consent and violating the Gateway API cross-namespace authorization model. This issue is fixed in versions 1.7.4 and 1.8.1.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L","score":6.4},"cwes":["CWE-862"],"references":["https://github.com/envoyproxy/gateway/commit/5a78db82b7cf4fc5bebbeda2c50952892038a464","https://github.com/envoyproxy/gateway/commit/96e2b750868a459ace4b8b68e6a6e4fb0152b9b7","https://github.com/envoyproxy/gateway/commit/b4737180c7e597490c6363075c565fa8cf24eead","https://github.com/envoyproxy/gateway/pull/9171","https://github.com/envoyproxy/gateway/pull/9172"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:53:43.293028046+00:00"},"epss":{"cve":"CVE-2026-53718","score":0.00413,"percentile":0.35595,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-fcrp-7gc2-93g7","url":"https://osv.dev/vulnerability/GHSA-fcrp-7gc2-93g7","summary":"Envoy Gateway custom backendRef cross-namespace ReferenceGrant bypass","modified":"2026-09-21T09:40:46.638359063Z","packages":[{"ecosystem":"Go","name":"github.com/envoyproxy/gateway","purl":"pkg:golang/github.com/envoyproxy/gateway","ranges":[">=1.8.0-rc.0 <1.8.1"],"fixed":["1.8.1"]},{"ecosystem":"Go","name":"github.com/envoyproxy/gateway","purl":"pkg:golang/github.com/envoyproxy/gateway","ranges":["<1.7.4"],"fixed":["1.7.4"]}]},{"id":"GO-2026-6007","url":"https://osv.dev/vulnerability/GO-2026-6007","summary":"Envoy Gateway custom backendRef cross-namespace ReferenceGrant bypass in github.com/envoyproxy/gateway","modified":"2026-09-21T09:40:46.638359063Z","packages":[{"ecosystem":"Go","name":"github.com/envoyproxy/gateway","purl":"pkg:golang/github.com/envoyproxy/gateway","ranges":["<1.7.4",">=1.8.0-rc.0 <1.8.1"],"fixed":["1.7.4","1.8.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}