Use of Non-Canonical URL Paths for Authorization Decisions in envoy - CVE-2026-73551
Published: August 26, 2026
Vulnerability identifier: #VU145861
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-73551
CWE-ID: CWE-647
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass path-based authorization or routing policies.
The vulnerability exists due to use of non-canonical url paths for authorization decisions in URL path normalization and path matching when handling HTTP requests with path segments containing dot or dotdot parameters. A remote attacker can send a specially crafted request to bypass path-based authorization or routing policies.
The issue can also cause path confusion between Envoy and an upstream service.
Affected software
envoy
Istio
Istio
How to mitigate CVE-2026-73551
Install security update from vendor's website.
envoy - addressed in versions 1.36.10, 1.37.6, 1.38.4, 1.39.1
Istio - addressed in versions 1.29.7, 1.30.4
Istio - addressed in versions 1.29.7, 1.30.4