CVE-2026-73511

Envoy: Potential path-matching/authentication bypass when using Envoy in combination with a backend stripping per-segment path (matrix) parameters (e.g. Apache Tomcat)

Published 21 Sep 2026 • Updated 21 Sep 2026

Severity: MEDIUM

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 normally matches the raw request path, while servlet backends such as Apache Tomcat strip semicolon matrix parameters from each path segment before resolving the resource. Envoy's ignore_path_parameters_in_path_matching option instead truncates at the first semicolon and still does not match per-segment backend behavior. A remote client can use a parameterized protected segment, or a parameter on an earlier segment, to make Envoy select an unprotected fallback while the backend resolves the protected resource. The relevant scope boundary is that the bypass requires both a path-based Envoy decision and a backend that strips semicolon parameters per segment. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

Affected products (1)

• envoyproxy envoy

Problem types

• CWE-289: Authentication Bypass by Alternate Name
• CWE-436: Interpretation Conflict

References (9)

• https://github.com/envoyproxy/envoy/security/advisories/GHSA-m745-gh6x-349x
• https://github.com/envoyproxy/envoy/commit/26d5
• https://github.com/envoyproxy/envoy/commit/50f7bfa48dccfee339822e9846b2b8053e07d325
• https://github.com/envoyproxy/envoy/commit/b205d1f4982e14ce5693ba94ef84d37e7155e050
• https://github.com/envoyproxy/envoy/commit/fcb663752c7055257f5dcc8b6ce6c7c905ebb1ff
• https://github.com/envoyproxy/envoy/releases/tag/v1.36.10
• https://github.com/envoyproxy/envoy/releases/tag/v1.37.6
• https://github.com/envoyproxy/envoy/releases/tag/v1.38.4
• https://github.com/envoyproxy/envoy/releases/tag/v1.39.1