CVE-2026-101057

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.

CVSS v3 3.1 LOW

3.1^/10

CVSS v3 : LOW

Vector :

Exploitability : 1.6 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact LOW

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/universal-tool-calling-protocol/python-utcp/security/advisories/GHSA-qwr9-cj2c-v3fv
https://www.vulncheck.com/advisories/utcp-mcp-before-1.1.3-ssrf-via-unvalidated-mcp-server-url

Configurations

No configuration.

History

27 Sep 2026, 18:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-09-27 18:16

Updated : 2026-09-30 17:32

NVD link : CVE-2026-101057

Mitre link : CVE-2026-101057

CVE.ORG link : CVE-2026-101057

JSON object : View

Products Affected

No product.

CWE

CWE-319

Cleartext Transmission of Sensitive Information

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