CVE-2026-53713
CRITICALCVE-2026-53713 is a critical-severity (CVSS 9.1) vulnerability in github.com/envoyproxy/gateway. O3 Security confirms whether CVE-2026-53713 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Envoy Gateway: Authentication Bypass via Improper Input Validation in EnvoyExtensionPolicy Lua Allows Secret Disclosure
Real-World Exposure
github.com/envoyproxy/gateway🐹github.com/envoyproxy/gatewayReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
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.
Patches
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/.).
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/envoyproxy/gateway | ≥ 1.8.0-rc.0&&< 1.8.1 | 1.8.1 |
| 🐹Go | github.com/envoyproxy/gateway | all versions | 1.7.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/envoyproxy/gateway. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/envoyproxy/gateway to 1.8.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-53713 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-53713 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-53713. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-53713 in your dependencies?
O3 detects CVE-2026-53713 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.