Is CVE-2026-55604 being exploited?

No public exploit is currently tracked.

How severe is CVE-2026-55604?

CVE-2026-55604 has a CVSS v3 severity of HIGH (8.6).

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CVE-2026-55604

Description

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.