CVE-2026-116686mediumCWE-918

CVE-2026-116686: fallo de gravedad media en modelcontextprotocol python-sdk

Model Context Protocol Python SDK: Client fetched server-chosen $ref URLs while validating tool results against output schemas

Publicada el · Actualizada el

Seguir esta CVE+ Monitorear python-sdk+ Monitorear mcp

Aviso por correo cuando entre en el KEV, tenga PoC pública o suba de nota.

13Vexday Risk Score

Sin señal de explotación. Ningún artefacto público de explotación conocido hasta ahora.

ssvc Trackcvss 6.5epss 0.3%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Productos afectados
modelcontextprotocol · python-sdk
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