CVE-2026-73511

Received Received - Intake

Path Parameter Bypass in Envoy Proxy

Publication date: 2026-09-21

Last updated on: 2026-09-21

Assigner: GitHub, Inc.

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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-09-21

Last Modified

2026-09-21

Generated

2026-09-22

AI Q&A

2026-09-22

EPSS Evaluated

N/A

NVD

CVE-2026-73511

EUVD

EUVD-2026-84121

Affected Vendors & Products

Vendor	Product	Version / Range
envoy	envoy	1.36.10
envoy	envoy	1.37.6
envoy	envoy	1.38.4
envoy	envoy	1.39.1
envoy	envoy	to 1.36.10 (exc)
envoy	envoy	to 1.37.6 (exc)
envoy	envoy	to 1.38.4 (exc)
envoy	envoy	to 1.39.1 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-289	The product performs authentication based on the name of a resource being accessed, or the name of the actor performing the access, but it does not properly check all possible names for that resource or actor.
CWE-436	Product A handles inputs or steps differently than Product B, which causes A to perform incorrect actions based on its perception of B's state.

Attack-Flow Graph

Executive Summary

Envoy is a proxy that normally matches raw request paths, but servlet backends like Apache Tomcat strip semicolon matrix parameters from path segments before resolving resources. Envoy's ignore_path_parameters_in_path_matching option truncates paths at semicolons but does not match backend behavior. A remote client can exploit this by using parameterized segments to bypass protections while the backend resolves the intended resource.

Detection Guidance

Check Envoy version with 'envoy --version'. If using versions before 1.36.10, 1.37.6, 1.38.4, or 1.39.1, the system is vulnerable. Inspect configuration for 'ignore_path_parameters_in_path_matching' setting.

Impact Analysis

This vulnerability allows an attacker to bypass intended access controls by manipulating path parameters. If your system uses Envoy with servlet backends that strip semicolon parameters, an attacker could access protected resources indirectly through Envoy's misconfigured path matching.

Compliance Impact

This vulnerability could potentially allow unauthorized access to protected resources by bypassing path-based security controls in Envoy. For compliance standards like GDPR and HIPAA, which require strict access controls and data protection, such a bypass could lead to unauthorized data exposure or breaches, violating regulatory requirements for confidentiality and integrity.

Mitigation Strategies

Upgrade Envoy to version 1.36.10, 1.37.6, 1.38.4, or 1.39.1 or later. Disable 'ignore_path_parameters_in_path_matching' if enabled. Review path-based routing rules for potential bypasses.

Hi! I’m here to help you understand CVE-2026-73511. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70