CVE-2026-53713: Envoy Gateway: Authentication Bypass via Improper Input Validation in EnvoyExtensionPolicy Lua Allows Secret Disclosure

Should you act?

Critical, preconditions apply

Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.4%, percentile 36: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 36% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Needs an account (low (any account)). Exposure depends on who can log in.
• Only applies if your dependency tree includes github.com/envoyproxy/gateway (Go) >= 1.8.0-rc.0, < 1.8.1, fixed in 1.8.1; github.com/envoyproxy/gateway (Go) < 1.7.4, fixed in 1.7.4. Check your lockfile, including transitive dependencies.

What it is

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, toabsolutenormalizedpath in internal/gatewayapi/luavalidator/security.lua does not collapse redundant separators before iscriticalpath evaluates Lua submitted through EnvoyExtensionPolicy during default Strict validation. Linux resolves a double-slash absolute path as the corresponding single-slash path, but the validator does not match the redundant-separator form, allowing submitted Lua to read arbitrary files from the gateway controller pod. Exposed files can include Kubernetes service-account tokens, TLS certificates, and process environment data, and the disclosed credentials can provide access to sensitive Kubernetes API Server or Gateway xDS server information. This issue is fixed in versions 1.7.4 and 1.8.1.

From the GitHub advisory

Impact

The toabsolutenormalizedpath function (security.lua:28-43) does not collapse redundant path separators (// → /). On Linux, //etc/passwd is equivalent to /etc/passwd (POSIX path semantics), but iscriticalpath fails to match the double-slash variant because //etc/passwd does not start with /etc/.

This allows Lua code submitted as an EnvoyExtensionPolicy to read arbitrary files from the gateway controller pod's filesystem during Strict validation (the default), including:

/etc/passwd Kubernetes SA tokens via //var/run/secrets/kubernetes.io/serviceaccount/token TLS certificates via //certs/... Process environment via //proc/self/environ

These credentials can be used to read sensitive information from the K8s API Server or from the Gateway XDS server.

Weakness type: CWE-20.

Product: github.com/envoyproxy/gateway (Go) · Assigned by: GitHub_M · Published: 2026-09-14

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: low (any account)
• User interaction: none
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable no, technical impact partial.
• FIRST EPSS (model of 2026-10-21): 0.43% probability of exploitation activity in the next 30 days; percentile 36.

Timeline

• 2026-07-16 — GitHub-reviewed advisory GHSA-wcrf-9vrr-854f published (critical)
• 2026-09-14 — CVE record published by GitHub_M
• 2026-09-16 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-wcrf-9vrr-854f github.com
2. CVE.org record CVE-2026-53713 cve.org
3. NVD entry CVE-2026-53713 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
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7. github.com github.com
8. github.com github.com
9. github.com github.com

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