CVE-2026-73551

Envoy: Path normalization does not handle dot and dotdot segments with parameters

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's URL normalization does not recognize dot and dotdot path segments when they carry semicolon parameters. A request such as /user/..;foo=bar/admin is therefore not canonicalized to /admin even when path normalization is enabled. If an upstream interprets the segment according to RFC 3986 while Envoy applies routing or RBAC to the uncollapsed path, a remote client can cause path confusion and bypass path-based security policy. The relevant scope boundary is that the security consequence depends on a downstream/upstream path interpretation mismatch or a path-based Envoy decision. 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-647: Use of Non-Canonical URL Paths for Authorization Decisions

References (9)

• https://github.com/envoyproxy/envoy/security/advisories/GHSA-2w8w-rfw7-8gg4
• https://github.com/envoyproxy/envoy/commit/28b6d60a6d96edeece121cac5be701eb46cc7f24
• https://github.com/envoyproxy/envoy/commit/d40a68b0a30a003c4e0a9fd3af637f828b52c37b
• https://github.com/envoyproxy/envoy/commit/e9d6c329f9a3ff19432bf39b60c601df7e3eda33
• https://github.com/envoyproxy/envoy/commit/f74d1107c4f5c9679b66f7a03a6c5b75ddde1989
• 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