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TI-2026-34792 Aliases CVE-2026-47204

Envoy: grpc_stats filter segfault on Connect protocol requests to direct_response routes

Priority HIGH 66CWE-476Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 4 fixed, 1 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-476.

Summary

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.26.0 until 1.35.13, 1.36.9, 1.37.5, and 1.38.3, the envoy.filters.http.grpc_stats filter crashes (null pointer dereference / segfault) when a Connect protocol request (Content-Type: application/connect+proto or application/connect+json) hits a direct_response route. A single unauthenticated HTTP request crashes the Envoy process. This vulnerability is fixed in 1.35.13, 1.36.9, 1.37.5, and 1.38.3.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00448 39th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial envoy (envoyproxy): 1.38.3, 1.37.5, 1.36.9 +1Red Hat: 4 advisoriesRed Hat: 4 fixed, 1 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
envoyproxyenvoy1.38.0 to before 1.38.3; 1.37.0 to before 1.37.5; 1.36.0 to before 1.36.9; 1.26.0 to before 1.35.131.38.3, 1.37.5, 1.36.9, 1.35.13Patch availableCNA
  • envoy Vendorenvoyproxy Affected 1.38.0 to before 1.38.3; 1.37.0 to before 1.37.5; 1.36.0 to before 1.36.9; 1.26.0 to before 1.35.13 Fixed in 1.38.3, 1.37.5, 1.36.9, 1.35.13 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*1.26.0 to before 1.35.13; 1.36.0 to before 1.36.9; 1.37.0 to before 1.37.5; 1.38.0 to before 1.38.3Vulnerableenvoyproxy
  • cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* Versions 1.26.0 to before 1.35.13; 1.36.0 to before 1.36.9; 1.37.0 to before 1.37.5; 1.38.0 to before 1.38.3 Vulnerable ·envoyproxy

Remediation

  • Fix · CNA envoy (envoyproxy) Fixed in 1.38.3, 1.37.5, 1.36.9, 1.35.13

Red Hat 4 advisories

  • RHSA-2026:49765 Released 2026-08-03 · Red Hat rating Important
    Red Hat OpenShift Service Mesh 3.3.6
    • Red Hat OpenShift Service Mesh 3.3 registry.redhat.io/openshift-service-mesh/istio-cni-rhel9, registry.redhat.io/openshift-service-mesh/istio-pilot-rhel9, registry.redhat.io/openshift-service-mesh/istio-proxyv2-rhel9 +1
  • RHSA-2026:49744 Released 2026-08-03 · Red Hat rating Important
    Red Hat OpenShift Service Mesh 3.2.8
    • Red Hat OpenShift Service Mesh 3.2 registry.redhat.io/openshift-service-mesh/istio-cni-rhel9, registry.redhat.io/openshift-service-mesh/istio-pilot-rhel9, registry.redhat.io/openshift-service-mesh/istio-proxyv2-rhel9 +1
  • RHSA-2026:49729 Released 2026-08-03 · Red Hat rating Important
    Red Hat OpenShift Service Mesh 3.1.11
    • Red Hat OpenShift Service Mesh 3.1 registry.redhat.io/openshift-service-mesh/istio-cni-rhel9, registry.redhat.io/openshift-service-mesh/istio-pilot-rhel9, registry.redhat.io/openshift-service-mesh/istio-proxyv2-rhel9 +1
Show 1 more Red Hat advisories
  • RHSA-2026:49705 Released 2026-08-03 · Red Hat rating Important
    Red Hat OpenShift Service Mesh 3.0.14
    • Red Hat OpenShift Service Mesh 3.0 registry.redhat.io/openshift-service-mesh/istio-cni-rhel9, registry.redhat.io/openshift-service-mesh/istio-pilot-rhel9, registry.redhat.io/openshift-service-mesh/istio-proxyv2-rhel9 +1

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
OpenShift Service Mesh 2AffectedNo fix planned: Will not fix
Red Hat OpenShift Service Mesh 3.0Fixed RHSA-2026:49705
Red Hat OpenShift Service Mesh 3.1Fixed RHSA-2026:49729
Red Hat OpenShift Service Mesh 3.2Fixed RHSA-2026:49744
Red Hat OpenShift Service Mesh 3.3Fixed RHSA-2026:49765
Not affected: 4 products
  • Red Hat OpenShift Service Mesh 3.0
  • Red Hat OpenShift Service Mesh 3.1
  • Red Hat OpenShift Service Mesh 3.2
  • Red Hat OpenShift Service Mesh 3.3

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-47204

References

Exploit 1

  • TI-2026-79288 Out-of-bounds write in Google Brotli decoder KEVCVSS 4.0CRITICAL 9.2
  • TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
  • TI-2024-20001 HTTP/2: CPU exhaustion due to CONTINUATION frame flood CVSS 3.1HIGH 7.5
  • TI-2024-18524 HTTP/2: memory exhaustion due to CONTINUATION frame flood CVSS 3.1HIGH 7.5
  • TI-2023-12215 Envoy client may fake the header `x-envoy-original-path` CVSS 3.1CRITICAL 9.1
  • TI-2023-18002 Envoy vulnerable to OAuth2 credentials exploit with permanent validity CVSS 3.1CRITICAL 9.8
See all 126 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences