The Model Context Protocol Python SDK is the official Python SDK for Model Context Protocol servers and clients.
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.
Read at NIST National Vulnerability Database (CVE API 2.0)
- Vendor
- Modelcontextprotocol
- Product
- python-sdk
- CVSS v3.1
- 6.5 AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
- Fix
- available
- Weakness
- CWE-918
- Exposure class
- AI infrastructure
- NVD status
- Received
Why it ranks 13 (Routine)
- CVSS v3.1 6.5 medium
- Product class: AI infrastructure
- Fix available
- Recency: items published within 24 hours gain 15, within 72 hours 6, within 7 days 2.
Links
- NIST National Vulnerability Database (CVE API 2.0) (nvd.nist.gov)
- CVE-2026-116686 on this site · NVD · CVE.org · Vulnpedia
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