high severity · published 2026-11-05
An MCP server that shares one stateless HTTP transport, McpServer or Server instance among multiple clients matches messages to a connection only by the JSON-RPC request identifier, so a response can be handed to the wrong client. One connected client can then read content that was meant for a different client.
CVE: CVE-2026-111770
Source: NVD
FixLane has a reviewed fix procedure for this incident: a read-only check first, then the fix. Ask the Telegram bot, or connect an AI agent to the FixLane MCP server and call get_fix_prompt with incident id 817 and your operating system.