CVE-2026-55604

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.

CVSS 3.1

8.6CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L

EPSS

0.4% chance of exploitation in the next 30 days; higher than 30% of CVEs (scores of 2026-10-25)

CWE

CWE-639

Published

2026-07-09

Modified

2026-10-25

Record from

the NVD, synced 2026-10-25

Packages (OSV)

References

• https://github.com/arikusi/deepseek-mcp-server/releases/tag/v1.7.0
• https://github.com/arikusi/deepseek-mcp-server/security/advisories/GHSA-fh3r-g96v-f578
• https://github.com/arikusi/deepseek-mcp-server/security/advisories/GHSA-fh3r-g96v-f578

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