---
id: CVE-2026-101057
title: >-
  utcp-mcp (the MCP plugin of python-utcp) through 1.1.2 connects to the HTTP
  and WebSocket MCP server URLs given in a call template's mcpServers
  configuration without the ensure_secure_url validation that the HTTP-family
  plugins apply, so…
summary: >-
  utcp-mcp (the MCP plugin of python-utcp) through 1.1.2 connects to the HTTP
  and WebSocket MCP server URLs given in a call template's mcpServers
  configuration without the ensure_secure_url validation that the HTTP-family
  plugins apply, so…
severity: low
cvss: 3.1
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N'
cwe:
  - CWE-319
vendor: universal-tool-calling-protocol
product: python-utcp
affected:
  - python-utcp < 1.1.3
published: '2026-09-27'
updated: '2026-09-27'
sourceUpdated: '2026-09-27T18:16:31.823'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-101057'
references:
  - url: >-
      https://github.com/universal-tool-calling-protocol/python-utcp/security/advisories/GHSA-qwr9-cj2c-v3fv
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/utcp-mcp-before-1.1.3-ssrf-via-unvalidated-mcp-server-url
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-27T17:56:02.209Z'
---

## Overview

utcp-mcp (the MCP plugin of python-utcp) through 1.1.2 connects to the HTTP and WebSocket MCP server URLs given in a call template's mcpServers configuration without the ensure_secure_url validation that the HTTP-family plugins apply, so the HTTPS/WSS-or-loopback rule is not enforced. A call template naming a plain-HTTP, non-loopback MCP server URL is dialed as configured, exposing the MCP handshake to network interception and permitting cleartext connections to internal hosts. The mcpServers configuration is operator-authored rather than remote data, and the connection is an MCP handshake rather than an arbitrary request returning a body, which limits practical exploitation; the OAuth2 token_url credential path described in the original report was not reachable in the affected versions, because the OAuth2 handler was never invoked and the call template's auth field was not read. Fixed in utcp-mcp 1.1.3, which validates server URLs before any connection is made.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.