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3 vulnerabilities found for mcp_python_sdk by lfprojects

FKIE_CVE-2025-66416

Vulnerability from fkie_nvd - Published: 2025-12-02 19:15 - Updated: 2026-03-10 19:40
Severity ?
8.1 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Summary
The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to version 1.23.0, tThe Model Context Protocol (MCP) Python SDK does not enable DNS rebinding protection by default for HTTP-based servers. When an HTTP-based MCP server is run on localhost without authentication using FastMCP with streamable HTTP or SSE transport, and has not configured TransportSecuritySettings, a malicious website could exploit DNS rebinding to bypass same-origin policy restrictions and send requests to the local MCP server. This could allow an attacker to invoke tools or access resources exposed by the MCP server on behalf of the user in those limited circumstances. Note that running HTTP-based MCP servers locally without authentication is not recommended per MCP security best practices. This issue does not affect servers using stdio transport. This vulnerability is fixed in 1.23.0.
References
security-advisories@github.comhttps://github.com/modelcontextprotocol/python-sdk/commit/d3a184119e4479ea6a63590bc41f01dc06e3fa99Patch
security-advisories@github.comhttps://github.com/modelcontextprotocol/python-sdk/security/advisories/GHSA-9h52-p55h-vw2fVendor Advisory
Impacted products
Vendor Product Version
lfprojects mcp_python_sdk *
To clipboard 

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CVE-2025-66416 (GCVE-0-2025-66416)

Vulnerability from nvd – Published: 2025-12-02 18:14 – Updated: 2025-12-02 18:45
VLAI?
Title
DNS Rebinding Protection Disabled by Default in Model Context Protocol Python SDK for Servers Running on Localhost
Summary
The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to version 1.23.0, tThe Model Context Protocol (MCP) Python SDK does not enable DNS rebinding protection by default for HTTP-based servers. When an HTTP-based MCP server is run on localhost without authentication using FastMCP with streamable HTTP or SSE transport, and has not configured TransportSecuritySettings, a malicious website could exploit DNS rebinding to bypass same-origin policy restrictions and send requests to the local MCP server. This could allow an attacker to invoke tools or access resources exposed by the MCP server on behalf of the user in those limited circumstances. Note that running HTTP-based MCP servers locally without authentication is not recommended per MCP security best practices. This issue does not affect servers using stdio transport. This vulnerability is fixed in 1.23.0.
Severity ?
7.6 (High)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CWE
  • CWE-1188 - Insecure Default Initialization of Resource
Assigner
References
Impacted products
Vendor Product Version
modelcontextprotocol python-sdk Affected: < 1.23.0
Create a notification for this product.
Show details on NVD website
To clipboard 

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CVE-2025-66416 (GCVE-0-2025-66416)

Vulnerability from cvelistv5 – Published: 2025-12-02 18:14 – Updated: 2025-12-02 18:45
VLAI?
Title
DNS Rebinding Protection Disabled by Default in Model Context Protocol Python SDK for Servers Running on Localhost
Summary
The MCP Python SDK, called `mcp` on PyPI, is a Python implementation of the Model Context Protocol (MCP). Prior to version 1.23.0, tThe Model Context Protocol (MCP) Python SDK does not enable DNS rebinding protection by default for HTTP-based servers. When an HTTP-based MCP server is run on localhost without authentication using FastMCP with streamable HTTP or SSE transport, and has not configured TransportSecuritySettings, a malicious website could exploit DNS rebinding to bypass same-origin policy restrictions and send requests to the local MCP server. This could allow an attacker to invoke tools or access resources exposed by the MCP server on behalf of the user in those limited circumstances. Note that running HTTP-based MCP servers locally without authentication is not recommended per MCP security best practices. This issue does not affect servers using stdio transport. This vulnerability is fixed in 1.23.0.
Severity ?
7.6 (High)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CWE
  • CWE-1188 - Insecure Default Initialization of Resource
Assigner
References
Impacted products
Vendor Product Version
modelcontextprotocol python-sdk Affected: < 1.23.0
Create a notification for this product.
Show details on NVD website
To clipboard 

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