Interpretation Conflict in envoy - CVE-2026-73553
Published: August 26, 2026
Vulnerability identifier: #VU145867
CSH Severity: Medium
CVSS v4: 8.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-73553
CWE-ID: CWE-436
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass path-based authorization controls.
The vulnerability exists due to inconsistent path canonicalization in the envoy router and RBAC url_path matcher when handling requests with path parameters while path-parameter stripping is enabled. A remote attacker can send a specially crafted request path containing a semicolon suffix to bypass path-based authorization controls.
Exploitation requires ignore_path_parameters_in_path_matching to be enabled, a path-based RBAC url_path policy to be configured, and the protected route to match after stripping the path parameter suffix.
Affected software
envoy
Istio
Istio
How to mitigate CVE-2026-73553
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