Permissive CORS in Apache Helix REST API

Executive Summary

CVE-2026-57111 is a vulnerability in Apache Helix REST API versions through 2.0.0 caused by a permissive Cross-Origin Resource Sharing (CORS) configuration in the helix-rest component's CORSFilter class.

This misconfiguration allows a remote attacker who controls a web page visited by an authorized user to read responses from and send cross-origin requests to administrative REST endpoints.

The issue arises because the CORS filter unconditionally returns Access-Control-Allow-Origin: * together with Access-Control-Allow-Credentials: true, and it reflects arbitrary Access-Control-Request-Method and Access-Control-Request-Headers values in preflight responses.

This means that the attacker can bypass same-origin policy restrictions and interact with sensitive administrative endpoints via cross-origin requests.

Users are recommended to upgrade to version 2.0.1 or later to fix this issue.

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Impact Analysis

This vulnerability can allow an attacker who controls a malicious web page to perform unauthorized cross-origin requests to administrative REST endpoints of Apache Helix.

Because the CORS configuration is overly permissive, the attacker can read sensitive responses and potentially perform actions with the privileges of an authorized user who visits the malicious page.

This could lead to unauthorized access to administrative functions, data leakage, or manipulation of the system through the REST API.

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Detection Guidance

This vulnerability can be detected by inspecting the HTTP response headers of the Apache Helix REST API endpoints to check for permissive CORS settings.

• Look for the presence of the header 'Access-Control-Allow-Origin' set to '*' together with 'Access-Control-Allow-Credentials' set to 'true'.
• Check if the server reflects arbitrary 'Access-Control-Request-Method' and 'Access-Control-Request-Headers' values in preflight (OPTIONS) responses.

You can use curl commands to test this behavior, for example:

• curl -i -X OPTIONS https://your-helix-server/rest-endpoint -H "Origin: http://example.com" -H "Access-Control-Request-Method: POST" -H "Access-Control-Request-Headers: X-Custom-Header"
• Then inspect the response headers for 'Access-Control-Allow-Origin: *' and 'Access-Control-Allow-Credentials: true' along with reflected request method and headers.

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Mitigation Strategies

The immediate and recommended step to mitigate this vulnerability is to upgrade Apache Helix REST to version 2.0.1 or later, where this issue is fixed.

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Compliance Impact

The provided information does not specify how this vulnerability affects compliance with common standards and regulations such as GDPR or HIPAA.

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