CVE-2026-73511: CWE-289: Authentication Bypass by Alternate Name in envoyproxy envoy
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.
AI Analysis
Technical Summary
Envoy proxy versions prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1 perform raw request path matching, whereas some servlet backends such as Apache Tomcat strip semicolon matrix parameters from each path segment before resource resolution. Envoy's ignore_path_parameters_in_path_matching option truncates the path at the first semicolon but does not replicate the per-segment stripping behavior of the backend. This mismatch allows a remote attacker to craft a request with semicolon parameters that cause Envoy to select an unprotected fallback resource, while the backend resolves the intended protected resource, effectively bypassing authentication. The vulnerability is fixed in the specified versions.
Potential Impact
An attacker can bypass authentication controls by exploiting the difference in path matching between Envoy and certain servlet backends that strip semicolon parameters per path segment. This can lead to unauthorized access to protected resources. The impact is limited to environments where Envoy is used with backends that perform per-segment semicolon parameter stripping, and where the ignore_path_parameters_in_path_matching option is in use or path-based decisions are made by Envoy.
Mitigation Recommendations
This issue is fixed in Envoy versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1. Users should upgrade to one of these versions or later to remediate the vulnerability. No additional mitigation steps are indicated by the vendor advisory.
CVE-2026-73511: CWE-289: Authentication Bypass by Alternate Name in envoyproxy envoy
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 v3.1
Score 5.3medium
Affected software
envoyproxy
envoy
pkg:github/envoyproxy/envoyRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Envoy proxy versions prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1 perform raw request path matching, whereas some servlet backends such as Apache Tomcat strip semicolon matrix parameters from each path segment before resource resolution. Envoy's ignore_path_parameters_in_path_matching option truncates the path at the first semicolon but does not replicate the per-segment stripping behavior of the backend. This mismatch allows a remote attacker to craft a request with semicolon parameters that cause Envoy to select an unprotected fallback resource, while the backend resolves the intended protected resource, effectively bypassing authentication. The vulnerability is fixed in the specified versions.
Potential Impact
An attacker can bypass authentication controls by exploiting the difference in path matching between Envoy and certain servlet backends that strip semicolon parameters per path segment. This can lead to unauthorized access to protected resources. The impact is limited to environments where Envoy is used with backends that perform per-segment semicolon parameter stripping, and where the ignore_path_parameters_in_path_matching option is in use or path-based decisions are made by Envoy.
Mitigation Recommendations
This issue is fixed in Envoy versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1. Users should upgrade to one of these versions or later to remediate the vulnerability. No additional mitigation steps are indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-08-12T19:00:33.736Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6ab1944855bf5e2cf56d7c25
Added to database: 09/21/2026, 20:32:08 UTC
Last enriched: 09/21/2026, 20:46:56 UTC
Last updated: 09/21/2026, 22:43:34 UTC
Views: 8
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