Summary
Envoy Gateway: Authentication Bypass via Improper Input Validation in EnvoyExtensionPolicy Lua Allows Secret Disclosure
Workarounds
Please refer to the Warning section in Lua docs for measures to reduce risk.
Credits
Envoy Gateway thanks @dashingDragon and @Donjon-Cerberus for reporting this issue.
Impact
The to_absolute_normalized_path function (security.lua:28-43) does not collapse redundant path separators (// → /). On Linux, //etc/passwd is equivalent to /etc/passwd (POSIX path semantics), but is_critical_path 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.
The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths. Typical impact: varies by context: data corruption, logic bypass, or denial of service.
CVE-2026-53713 has a CVSS score of 9.1 (Critical). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.8.1, 1.7.4); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Already deployed Kodem?
See it in your environmentNew to Kodem? Get a demo →Remediation advice
This has been patched in versions >= v1.7.4 and v1.8.1
- Collapse redundant path separators (
//to/) so double-slash variants like//etc/passwdand//var/run/secrets/...are matched by the critical-path check. - Rewrite the traversal check to reject any
.or..segment in any position and across both separator styles (catches/etc/./passwd,./etc/passwd,/etc/.).
Frequently Asked Questions
- What is CVE-2026-53713? CVE-2026-53713 is a critical-severity improper input validation vulnerability in github.com/envoyproxy/gateway (go), affecting versions >= 1.8.0-rc.0, < 1.8.1. It is fixed in 1.8.1, 1.7.4. The application does not adequately validate input before processing it, allowing unexpected values to reach sensitive code paths.
- How severe is CVE-2026-53713? CVE-2026-53713 has a CVSS score of 9.1 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/envoyproxy/gateway are affected by CVE-2026-53713? github.com/envoyproxy/gateway (go) versions >= 1.8.0-rc.0, < 1.8.1 is affected.
- Is there a fix for CVE-2026-53713? Yes. CVE-2026-53713 is fixed in 1.8.1, 1.7.4. Upgrade to this version or later.
- Is CVE-2026-53713 exploitable, and should I be worried? Whether CVE-2026-53713 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-53713 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-53713?
- Upgrade
github.com/envoyproxy/gatewayto 1.8.1 or later - Upgrade
github.com/envoyproxy/gatewayto 1.7.4 or later
- Upgrade