CVE-2026-53718Network attack vectorHinoki check available

Cross-namespace backend access via omitted authorization check

Published Sep 14, 2026 · Updated Sep 14, 2026

Authorization bypass in Envoy Gateway before 1.7.4 and 1.8.0-rc.0 through 1.8.0 allows remote authenticated users to route traffic. The custom-backend branch in internal/gatewayapi/route.go skips validateBackendNamespace, so it never verifies the required ReferenceGrant. Reachability requires permission to create HTTPRoutes and enable extension-managed custom backends; the bypass grants cross-namespace use without the backend owner's consent.

CVSS severity6.4
Medium
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Authorization bypass in Envoy Gateway before 1.7.4 and 1.8.0-rc.0 through 1.8.0 allows remote authenticated users to route traffic. The custom-backend branch in internal/gatewayapi/route.go skips validateBackendNamespace, so it never verifies the required ReferenceGrant. Reachability requires permission to create HTTPRoutes and enable extension-managed custom backends; the bypass grants cross-namespace use without the backend owner's consent.

The record

CVE
CVE-2026-53718
Published
Sep 14, 2026
Updated
Sep 14, 2026
Vendor
Envoy Proxy
Product
Envoy Gateway
Classifications
CWE-862, T1210
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.7.4
  2. Affected versionversion=>= 1.8.0-rc.0, < 1.8.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Envoy Proxy · Envoy Gatewayversion=< 1.7.4; version=>= 1.8.0-rc.0, < 1.8.1

Published CVSS scores

6.4GitHubCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-862Missing Authorization
T1210Exploitation of Remote Services

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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