Threats tagged 'brew-mcp-atlassian-cve-2026-116686'

The Model Context Protocol (MCP) Python SDK client versions 1.10.0 through 1.29.1 and 2.0.0 through 2.1.1 have a vulnerability where the client fetches server-chosen $ref URLs during tool output schema validation. This causes the client to synchronously request external HTTP, HTTPS, or local file URLs on every tool call, potentially stalling the client if the target is unresponsive. The issue is fixed in versions 1.30.0 and 2.2.0 or later by restricting reference resolution to within the schema document only.