Unrated

Unauthenticated exposed MCP server in mcp-pinot leading to Apache Pinot cluster access

IdentifiersCVE-2026-49257CWE-306

CVE-2026-49257 affects mcp-pinot, a Python-based Model Context Protocol (MCP) server for Apache Pinot. In mcp-pinot 3.0.1 and earlier, the product defaults to exposing an HTTP MCP service on 0.0.0.0:8080 with authentication disabled. As a result, any network-adjacent caller can invoke exposed MCP tools without authentication. These tools include SQL query execution, schema creation, and table-configuration mutation. Because mcp-pinot forwards these operations using its configured server-side Pinot credentials, the flaw creates a confused-deputy condition in which unauthenticated external users can perform actions against the backend Pinot cluster with the server's privileges. The issue is fixed in version 3.1.0.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can give an unauthenticated network-adjacent attacker full read and write access to the configured Apache Pinot cluster through the MCP server's backend credentials. This includes executing SQL queries, creating schemas, and modifying table configurations. Depending on the privileges assigned to the server-side Pinot account, the attacker may be able to access sensitive data, alter cluster metadata and configuration, disrupt service operation, and compromise the integrity and availability of the Pinot environment.

Mitigation

If you can’t patch tonight, do this now.

If immediate upgrade is not possible, restrict network access to the MCP server so that only trusted administrative or application hosts can reach it, using firewall rules, security groups, reverse proxies, or bind-address restrictions. Enable authentication on the MCP server if supported in the deployed configuration. As a defense-in-depth measure, rotate and minimize the privileges of the Pinot credentials configured on the server and monitor for unauthorized SQL execution, schema creation, or table-configuration changes.

Remediation

Patch, then assume compromise.

Upgrade mcp-pinot to version 3.1.0 or later, which fixes the insecure default behavior. Review the MCP server configuration to ensure authentication is enabled and verify that the service is not unnecessarily exposed on 0.0.0.0:8080 or other untrusted network interfaces. Also review and reduce the privileges of the Pinot credentials used by the server where possible, consistent with least-privilege operation.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

ACTIVITY FEED

Recent activity

7 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

7 SOURCESView more in app

cvefeed high severityNews

Jun 18, 2026

CVE-2026-49257 - mcp-pinot: Unauthenticated tool invocation via default oauth_enabled=False + host 0.0.0.0 bind

An authentication bypass / unauthenticated tool invocation vulnerability in mcp-pinot that exposes MCP tools over a network-accessible HTTP server with oauth_enabled=False by default, allowing network-adjacent attackers to gain full read/write access to the configured Apache Pinot cluster via server-side credentials.

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity6

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-49257

NVD

nvd.nist.gov/vuln/detail/CVE-2026-49257

MITRE CWE · CWE-306

cwe.mitre.org