CVE-2026-73547: Envoyproxy Envoy

High severity, CVSS 7.5. EPSS: 0.6% chance of exploitation in the next 30 days.

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.

Affected products

• Envoyproxy Envoy: before 1.36.10 (fixed in 1.36.10); from 1.37.0, before 1.37.6 (fixed in 1.37.6); from 1.38.0, before 1.38.4 (fixed in 1.38.4); from 1.39.0, before 1.39.1 (fixed in 1.39.1)

Published 2026-09-21. Last modified 2026-10-06.