All vulnerabilities
CVE-2026-101057GHSA-qwr9-cj2c-v3fv

python-utcp: utcp-mcp before 1.1.3 SSRF via unvalidated MCP server URL

universal-tool-calling-protocol python-utcpRuntimes & languages
CVSS
2.3Low
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.11%Chance of exploitation activity in the next 30 days, higher than 1% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in1.1.3Fixed versionCVE List
Published27 Sep 2026Updated 30 Sep 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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.

Text from CVE List

Affected versions 2

  • python-utcpaffected: all versions before 1.1.3CVE List
  • python-utcpunaffected: 1.1.3CVE List

References 2