CVE-2026-47204: Envoy: grpc_stats filter segfault on Connect protocol requests to direct_response routes

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-06-26 · updated 2026-10-25
Weakness: CWE-476

Description

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.

Affected products

envoyproxy envoy: from 1.26.0 before 1.35.13; from 1.36.0 before 1.36.9; from 1.37.0 before 1.37.5; from 1.38.0 before 1.38.3 — fixed in 1.35.13, 1.36.9, 1.37.5, 1.38.3

How to fix

Upgrade to a fixed version: envoyproxy envoy 1.35.13, 1.36.9, 1.37.5, 1.38.3. Check the vendor advisory for mitigations.

References

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