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CVE-2026-59951

CVE-2026-59951 · MCP Python SDK: Unbounded Session Accumulation in StreamableHTTP Transport Enables Resource Exhaustion

Esta página presenta datos de fuentes públicas de vulnerabilidades. Consulta el aviso original antes de actualizar.

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 6.9 · Media · EPSS 0,5% · Corrección disponible

Publicación
Actualización

Pila tecnológica: python

Productos y versiones afectados

  • python-sdk

    Versiones
    • >= 1.8.0, < 1.30.0: Afectada
    • >= 2.0.0, < 2.2.0: Afectada

    Sin corrección publicada

  • mcp PyPI

    Versiones
    • 1.10.0
    • 1.10.1
    • 1.11.0
    • 1.12.0
    • 1.12.1
    • 1.12.2
    • 1.12.3
    • 1.12.4
    • 1.13.0
    • 1.13.1
    • 1.14.0
    • 1.14.1
    • 1.15.0
    • 1.16.0
    • 1.17.0
    • 1.18.0
    • 1.19.0
    • 1.20.0
    • 1.21.0
    • 1.21.1
    • 1.21.2
    • 1.22.0
    • 1.23.0
    • 1.23.1
    • 1.23.2
    • 1.23.3
    • 1.24.0
    • 1.25.0
    • 1.26.0
    • 1.27.0
    • 1.27.1
    • 1.27.2
    • 1.28.0
    • 1.28.1
    • 1.29.0
    • 1.29.1
    • 1.8.0
    • 1.8.1
    • 1.9.0
    • 1.9.1
    • 1.9.2
    • 1.9.3
    • 1.9.4
    Intervalos de versiones afectados
    • ECOSYSTEM: ≥ 1.8.0, < 1.30.0

    Actualiza a 1.30.0

  • mcp PyPI

    Versiones
    • 2.0.0
    • 2.0.1
    • 2.1.0
    • 2.1.1
    Intervalos de versiones afectados
    • ECOSYSTEM: ≥ 2.0.0, < 2.2.0

    Actualiza a 2.2.0

Fuentes originales

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