Model Context Protocol Python SDK: Client fetched server-chosen $ref URLs while validating tool results against output schemas
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| modelcontextprotocol | python-sdk | affected |
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| Modelcontextprotocol | Python-sdk |
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| Source | ID | Title |
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Github GHSA |
GHSA-rwrf-2pqf-9j8j | Model Context Protocol Python SDK: Client fetched server-chosen $ref URLs while validating tool results against output schemas |
No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.337% probability within 30 days)
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| Weaknesses | CWE-1322 | |
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threat_severity
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threat_severity
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| Metrics |
ssvc
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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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| Description | The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients. From 1.10.0 until 1.30.0 and 2.2.0, ClientSession, ClientSessionGroup, and Client tool calls validate server-declared outputSchema documents with jsonschema's default resolver, causing an unresolved $ref value to fetch an HTTP, HTTPS, or file URL from the client's network and filesystem context. A server can trigger blind requests or local-file reads and can stall every session in the process because resolution runs synchronously on the event loop without a timeout. This issue is fixed in versions 1.30.0 and 2.2.0. | |
| Title | Model Context Protocol Python SDK: Client fetched server-chosen $ref URLs while validating tool results against output schemas | |
| Weaknesses | CWE-918 | |
| References |
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| Metrics |
cvssV3_1
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