DNS Rebinding Protection Disabled by Default in Model Context Protocol Python SDK for Servers Running on Localhost
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
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| modelcontextprotocol | python-sdk | affected |
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No data.
| Vendor | Product | Versions |
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| Modelcontextprotocol | Python-sdk | — |
| Source | ID | Title |
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Github GHSA |
GHSA-9h52-p55h-vw2f | Model Context Protocol (MCP) Python SDK does not enable DNS rebinding protection by default |
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.544% probability within 30 days)
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Lfprojects
Lfprojects mcp Python Sdk |
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| CPEs | cpe:2.3:a:lfprojects:mcp_python_sdk:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Lfprojects
Lfprojects mcp Python Sdk |
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| First Time appeared |
Modelcontextprotocol
Modelcontextprotocol python-sdk |
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| Vendors & Products |
Modelcontextprotocol
Modelcontextprotocol python-sdk |
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threat_severity
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cvssV3_1
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ssvc
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| Description | 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. | |
| Title | DNS Rebinding Protection Disabled by Default in Model Context Protocol Python SDK for Servers Running on Localhost | |
| Weaknesses | CWE-1188 | |
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| Metrics |
cvssV4_0
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