CVE-2026-73547

High

Description

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1, Envoy's ext_authz filter assumes that a request contains a :path pseudoheader when applying query_parameters_to_set or query_parameters_to_remove from an authorization response. A path-less CONNECT request makes request_headers_->Path() return null, and Filter::onComplete dereferences that pointer while parsing the query string. An unauthenticated downstream client can crash the Envoy process when the filter and authorization response use query-parameter mutation. The relevant scope boundary is that the deployment must accept path-less CONNECT and configure ext_authz query-parameter mutation. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

SeverityHigh
CVSS7.5
Exploit probability—
ProductEnvoy
PublishedSep 21, 2026
First seenSep 21, 2026

How to fix

Update
  • envoyproxy envoy1.36.10, 1.37.6, 1.38.4, 1.39.1 or later

Affected products

ProductAffected versionsFixed in
envoyproxy envoyv < 1.36.10, 1.37.0 ≤ v < 1.37.6, 1.38.0 ≤ v < 1.38.4, 1.39.0 ≤ v < 1.39.11.36.10, 1.37.6, 1.38.4, 1.39.1

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