CVE-2026-49257
Received Received - Intake
HTTP MCP Server Authentication Bypass in mcp-pinot

Publication date: 2026-06-18

Last updated on: 2026-06-18

Assigner: GitHub, Inc.

Description
mcp-pinot is a Python-based Model Context Protocol (MCP) server for interacting with Apache Pinot. In versions 3.0.1 and below, mcp-pinot defaults to running an HTTP MCP server bound to 0.0.0.0:8080 with no authentication enabled. All MCP tools, including SQL query execution, schema creation, and table-config mutation, are reachable by any network-adjacent caller. The server proxies these calls using server-side Pinot credentials, producing a confused-deputy condition that yields full read/write access to the configured Pinot cluster. This issue has been fixed in version 3.1.0
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Meta Information
Published
2026-06-18
Last Modified
2026-06-18
Generated
2026-06-19
AI Q&A
2026-06-19
EPSS Evaluated
N/A
NVD
CVE-2026-49257
Affected Vendors & Products
Currently, no data is known.
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-306 The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
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Compliance Impact

This vulnerability allows unauthenticated network-adjacent attackers to gain full read and write access to the configured Apache Pinot cluster due to the MCP server running without authentication and exposing sensitive operations. Such unauthorized access to data and the ability to modify it can lead to violations of data protection and privacy regulations like GDPR and HIPAA, which require strict controls over access to personal and sensitive information.

Specifically, the lack of authentication and the confused-deputy condition enabling full control over the data can result in unauthorized disclosure, alteration, or destruction of protected data, thereby compromising confidentiality, integrity, and availability requirements mandated by these standards.

Executive Summary

The vulnerability exists in mcp-pinot, a Python-based Model Context Protocol server for Apache Pinot. In versions 3.0.1 and below, the server runs an HTTP MCP service bound to all network interfaces (0.0.0.0:8080) without any authentication. This means that anyone on the network can access all MCP tools, including executing SQL queries, creating schemas, and modifying table configurations. The server uses its own Pinot credentials to proxy these requests, leading to a confused-deputy problem that grants full read and write access to the Pinot cluster.

Impact Analysis

This vulnerability can have severe impacts as it allows any network-adjacent attacker to gain full read and write access to the configured Apache Pinot cluster. An attacker could execute arbitrary SQL queries, alter schemas, and modify table configurations without any authentication, potentially leading to data breaches, data corruption, or denial of service.

Mitigation Strategies

To mitigate this vulnerability, upgrade mcp-pinot to version 3.1.0 or later, where the issue has been fixed.

Until the upgrade can be performed, restrict network access to the MCP server to trusted hosts only, as it defaults to binding on 0.0.0.0:8080 with no authentication.

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