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Bypass of RBAC uri_template permission

Moderate
phlax published GHSA-c7cm-838g-6g67 May 7, 2025

Package

No package listed

Affected versions

<v1.34.1, <v1.33.3, <v1.32.6, <v1.31.8

Patched versions

v1.34.1, v1.33.3, v1.32.6, v1.31.8

Description

Summary

Envoy's URI template matcher does not match URI paths containing the * character.

Affected Components

Envoy's URI template matcher and Envoy's HTTP RBAC extension when configured with the uri_template permissions.

Details

Envoy's URI template matcher incorrectly excludes the * character from a set of valid characters in the URI path. As a result URI path containing the * character will not match a URI template expressions.

Impact

Bypass of RBAC rules when configured using the uri_template permissions.

Attack vector(s)

A request from an untrusted peer with URI path containing the * character.

Patches

This vulnerability is fixed in Envoy versions v1.34.1, v1.33.3, v1.32.6, v1.31.8

Workarounds

Configure additional RBAC permissions using url_path with safe_regex expression.

Detection

Access log entries to excluded endpoints with the * character(s) in request URI path.

Credits

Discovery: "Chwila, Bartosz" [email protected]
Diagnostics: Jackie Maertens (Elliott): https://github.com/jaellio

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVE ID

CVE-2025-46821

Weaknesses

Overly Restrictive Regular Expression

A regular expression is overly restrictive, which prevents dangerous values from being detected. Learn more on MITRE.

Credits