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CVE-2026-53718

Envoy Gateway custom backendRef cross-namespace ReferenceGrant bypass

Published: Sep 14, 2026Updated: Sep 14, 2026 Sources: CVE List NVDCWE-862
6.4MEDIUM
NVD MITRE
EPSS Score
N/A
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available
Self-Check
Not available

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:HPR:LUI:NS:UC:HI:LA:L
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:LIntegrity
Low
A:LAvailability
Low
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Weaknesses

CWE-862

Affected Products

envoyproxy
oss-project·USaka envoy proxy, envoy
gatewaySaaSSaaS Service
Cloud & SaaS / api-gateway

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques
Initial Access
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References

https://github.com/envoyproxy/gateway/commit/5a78db82b7cf4fc5bebbeda2c50952892038a464
github.com
https://github.com/envoyproxy/gateway/commit/96e2b750868a459ace4b8b68e6a6e4fb0152b9b7
github.com
https://github.com/envoyproxy/gateway/commit/b4737180c7e597490c6363075c565fa8cf24eead
github.com
and 6 more references View all →

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