Resource Exhaustion Affecting python-mcp package, versions *


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.46% (39th percentile)

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  • Snyk IDSNYK-DEBIANUNSTABLE-PYTHONMCP-21139785
  • published17 Oct 2026
  • disclosed14 Oct 2026

Introduced: 14 Oct 2026

NewCVE-2026-59951  (opens in a new tab)
CWE-400  (opens in a new tab)
CWE-772  (opens in a new tab)

How to fix?

There is no fixed version for Debian:unstable python-mcp.

NVD Description

Note: Versions mentioned in the description apply only to the upstream python-mcp package and not the python-mcp package as distributed by Debian. See How to fix? for Debian:unstable relevant fixed versions and status.

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.

CVSS Base Scores

version 3.1