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CVE-2026-57139 – Unauthenticated RCE via MCPServer HTTP Transport – PraisonAI 1.5.0–1.7.1

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Summary

CVE-2026-57139 is a critical missing-authentication vulnerability in PraisonAI’s MCPServer HTTP transport (npm package praisonai). The server’s startHttp() method binds to all network interfaces and processes Model Context Protocol (MCP) requests — including tools/call, tools/list, resources/read, and prompts/get — without any credential validation, allowing any network-reachable client to invoke registered tools and handlers. Given the network attack vector, lack of required privileges or user interaction, and the potential for full compromise of confidentiality, integrity, and availability, this vulnerability carries a CVSS score of 9.8 (Critical).

Technical details

  • Root cause: The MCPServerConfig interface contains no authentication or authorization fields, and the startHttp() method does not validate or even inspect the Authorization header on incoming requests. A MCPSecurity class exists in the codebase but is never wired into the HTTP request-handling path.
  • Trigger conditions: The MCP HTTP server binds to the unspecified address (::), exposing it on all network interfaces rather than restricting it to localhost (127.0.0.1), so any deployment that runs MCPServer.startHttp() without an external auth proxy is exposed.
  • Attack vector: Network — an unauthenticated remote attacker sends unauthenticated HTTP POST requests to the exposed MCP endpoint to invoke tools/list, tools/call, resources/read, or prompts/get.
  • Impact: Registered MCP tool handlers execute with the server process’s credentials and privileges. Because MCP tools commonly wrap filesystem access, external API calls, database queries, or code execution, an attacker can disclose sensitive registered data or achieve arbitrary code/command execution in the context of the server process.

Affected software

  • PraisonAI (npm package praisonai), versions >= 1.5.0 and <= 1.7.1
  • Fixed in version 1.7.2 and later

Severity

  • CVSS v3.1 Base Score: 9.8 (Critical)
  • Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Mitigation and recommended actions

  • Immediate: Upgrade PraisonAI (praisonai npm package) to version 1.7.2 or later, which addresses the missing authentication in the MCPServer HTTP transport.
  • If immediate patching is not possible:
    • Do not expose the MCP HTTP server directly to untrusted networks; restrict it to bind on 127.0.0.1 or place it behind a properly authenticated reverse proxy/API gateway.
    • Use network-level controls (firewall rules, security groups) to limit access to the MCP server port to trusted, internal hosts only.
    • Audit which MCP tools/handlers are registered and disable or restrict any that expose filesystem, database, or code-execution capabilities until the server is patched.

References

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