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CVE-2026-101057— utcp-mcp before 1.1.3 SSRF via unvalidated MCP server URL

Quick assessment

Affected
universal-tool-calling-protocol python-utcp
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

utcp-mcp（python-utcp 的 MCP 插件）在 1.1.2 及更早版本中，调用模板中 mcpServers 配置所指定的 HTTP 和 WebSocket MCP 服务器 URL 时，未应用 HTTP 系列插件所实施的 ensure_secure_url 安全验证，因此不会强制实施“仅允许 HTTPS/WSS 或本地回环地址”的策略。如果调用模板中配置了纯 HTTP 且非本地回环的 MCP 服务器 URL，系统会按配置直接发起连接，从而导致 MCP 握手过程暴露于网络中间人攻击之下，并允许向内部主机

CVSS 3.1 · Low

Possible ATT&CK Techniques 1 AI

T1071 · Application Layer Protocol
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I. Basic Information for CVE-2026-101057

Vulnerability Information
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Vulnerability Title
utcp-mcp before 1.1.3 SSRF via unvalidated MCP server URL
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
敏感数据的明文传输
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
universal-tool-calling-protocol python-utcp 0 ~ 1.1.3 -

II. Public POCs for CVE-2026-101057

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III. Intelligence Information for CVE-2026-101057

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Vendor Advisories for CVE-2026-101057 (1)

Other References for CVE-2026-101057 (1)

Same Patch Batch · universal-tool-calling-protocol · 2026-09-27 · 5 CVEs total

CVE-2026-101060 8.2 HIGH python-utcp before 1.1.4 SSRF via unvalidated HTTP redirects
CVE-2026-101059 7.1 HIGH utcp-http before 1.1.4 OAuth2 tokenUrl Trust Boundary Bypass
CVE-2026-101058 6.9 MEDIUM python-utcp before 1.1.12 SSRF via Remote HTTP Manual
CVE-2026-101061 4.7 MEDIUM utcp-gql and utcp-websocket before 1.1.1 SSRF via URL validation bypass

IV. Related Vulnerabilities

Same product: python-utcp
Same vendor: universal-tool-calling-protocol
Same weakness: CWE-319

V. Comments for CVE-2026-101057

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