CVE-2026-53718

mediumpriority · track · 0OT risk · elevatedEPSS 0.004 · 35 %ileUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
0.41% (35th) EPSS
CVSS 6.4 · medium
Is it mine?
4 products
Check your exposure
Who says so?
1 sources
osv

EPSS · scored 2026-10-27

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.

01

cvss

Technical severity, 0–10. One row per scoring source.

6.4
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.16.4mediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:Lsecondary · security-advisories@github.comexploitability 1.6 · impact 4.7
v3.16.4mediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:Lsecondary · OSV
v3.15.9mediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L/E:Usecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-862USCWE-862US
04

affected products (4)

Products and version ranges known to be affected.

05

advisories (3)

Vendor and ecosystem advisories describing this.

  • GHSA-fcrp-7gc2-93g7Envoy Gateway custom backendRef cross-namespace ReferenceGrant bypass2026-07-16ghsa · osvUS

    ### Impact Envoy Gateway accepts extension-managed custom backendRefs from an HTTPRoute to a backend resource in another namespace without requiring a matching Gateway API ReferenceGrant in the target namespace. This breaks the Gateway API cross-namespace consent model: the namespace that owns the referenced backend resource does not need to opt in with a ReferenceGrant before another namespace’s HTTPRoute can use that resource. ### Patches [1.7.4](https://github.com/envoyproxy/gateway/releases/tag/v1.7.4) [1.8.1](https://github.com/envoyproxy/gateway/releases/tag/v1.8.1)

  • BIT-envoy-gateway-2026-53718Envoy Gateway custom backendRef cross-namespace ReferenceGrant bypass2026-09-21vendor · osvUS

    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.

  • GO-2026-6007Envoy Gateway custom backendRef cross-namespace ReferenceGrant bypass in github.com/envoyproxy/gateway2026-07-17vendor · osvUS

    Envoy Gateway custom backendRef cross-namespace ReferenceGrant bypass in github.com/envoyproxy/gateway

06

also known as (3)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

osvNVDCVE.orgMITRE
published 2026-09-14modified 2026-09-25
08

references (9) nvd

External citations — patches, advisories, analysis.

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