CVE-2026-55604: Arikusi Deepseek-Mcp-Server

High severity, CVSS 8.6. EPSS: 0.4% chance of exploitation in the next 30 days.

DeepSeek MCP Server is an MCP server for DeepSeek V4. Starting in version 1.4.2 and prior to version 1.7.0, the process-global `SessionStore` accepts caller-supplied `session_id` values without binding them to any authenticated principal or transport session. An attacker can enumerate active session IDs via `deepseek_sessions`, then reuse a victim-controlled `session_id` in `deepseek_chat` to retrieve and continue the victim's conversation context. Version 1.7.0 contains a patch.

Affected products

• Arikusi Deepseek-Mcp-Server: from 1.4.2, before 1.7.0 (fixed in 1.7.0)

Published 2026-07-09. Last modified 2026-07-10.