universal-tool-calling-protocol python-utcp up to 1.1.2 utcp-mcp cleartext transmission

Summaryinfo

A vulnerability, which was classified as problematic, was found in universal-tool-calling-protocol python-utcp up to 1.1.2. This vulnerability affects unknown code of the component utcp-mcp. Such manipulation leads to cleartext transmission. This vulnerability is referenced as CVE-2026-101057. It is possible to launch the attack remotely. No exploit is available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in universal-tool-calling-protocol python-utcp up to 1.1.2. It has been rated as problematic. Affected by this issue is some unknown functionality of the component utcp-mcp. The manipulation with an unknown input leads to a cleartext transmission vulnerability. Using CWE to declare the problem leads to CWE-319. The product transmits sensitive or security-critical data in cleartext in a communication channel that can be sniffed by unauthorized actors. Impacted is confidentiality. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-101057 since 09/27/2026. The exploitation is known to be difficult. The attack may be launched remotely. No form of authentication is required for exploitation. The technical details are unknown and an exploit is not available. This vulnerability is assigned to T1040 by the MITRE ATT&CK project.

Upgrading to version 1.1.3 eliminates this vulnerability.

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Productinfo

Type

• Programming Language Software

Vendor

• universal-tool-calling-protocol

Name

• python-utcp

Version

• 1.1.0
• 1.1.1
• 1.1.2

Website

• Product: https://github.com/universal-tool-calling-protocol/python-utcp/

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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