Envoy Gateway: Authentication Bypass via Improper Input Validation in EnvoyExtensionPolicy Lua Allows Secret Disclosure

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

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, to_absolute_normalized_path in internal/gatewayapi/luavalidator/security.lua does not collapse redundant separators before is_critical_path 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.

Source published

14 Sep 2026 20:11:02 UTC

Source modified

16 Sep 2026 18:34:11 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 9.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L

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, to_absolute_normalized_path in internal/gatewayapi/luavalidator/security.lua does not collapse redundant separators before is_critical_path 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.

Source published

Sep 14, 2026, 8:11:02 PM (timezone not stated)

Source modified

Sep 16, 2026, 6:34:11 PM (timezone not stated)

Observed here

11 Nov 2026 13:10:46 UTC

Source terms

ENISA EUVD · source terms and attribution apply

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 9.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L

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, to_absolute_normalized_path in internal/gatewayapi/luavalidator/security.lua does not collapse redundant separators before is_critical_path 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.

Source published

14 Sep 2026 21:17:12 UTC

Source modified

30 Sep 2026 17:43:24 UTC

Observed here

25 Oct 2026 13:17:16 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 9.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L

### 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/passwd` and `//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](https://gateway.envoyproxy.io/v1.8/tasks/extensibility/lua/) for measures to reduce risk. ### Credits Envoy Gateway thanks @dashingDragon and @Donjon-Cerberus for reporting this issue.

Source published

16 Jul 2026 19:23:38 UTC

Source modified

21 Sep 2026 09:40:42 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L

Publisher rating · CRITICAL

Envoy Gateway: Authentication Bypass via Improper Input Validation in EnvoyExtensionPolicy Lua Allows Secret Disclosure in github.com/envoyproxy/gateway

Source published

17 Jul 2026 19:42:05 UTC

Source modified

21 Sep 2026 09:40:42 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.