MCP Python SDK: Unbounded Session Accumulation in StreamableHTTP Transport Enables Resource Exhaustion
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-84m7-p3x7-pcfv | MCP Python SDK: Unbounded Session Accumulation in StreamableHTTP Transport Enables Resource Exhaustion |
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.458% probability within 30 days)
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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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| Metrics |
threat_severity
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cvssV3_1
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| Metrics |
ssvc
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| Description | The MCP Python SDK, called mcp on PyPI, is a Python implementation of the Model Context Protocol (MCP). From 1.8.0 until 1.30.0 and 2.2.0, stateful Streamable HTTP servers, including FastMCP, MCPServer, Server.streamable_http_app(), and StreamableHTTPSessionManager, retain session entries without an idle expiration or aggregate session-count limit. DELETE, refused opening requests, and completed sessions do not reliably discard their entries, and each entry can retain parsed initialize parameters. A client that can reach the endpoint can therefore create ordinary short requests that grow server memory without bound until restart. Stateless HTTP, stdio, and SSE transports are not affected. This issue is fixed in versions 1.30.0 and 2.2.0. | |
| Title | MCP Python SDK: Unbounded Session Accumulation in StreamableHTTP Transport Enables Resource Exhaustion | |
| Weaknesses | CWE-400 CWE-772 |
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| References |
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| Metrics |
cvssV4_0
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