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TI-2026-40138 Aliases CVE-2026-55604GHSA-fh3r-g96v-f578

@arikusi/deepseek-mcp-server has an Authorization Bypass Through User-Controlled Key

Priority MEDIUM 43CWE-639Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
High · Low · Low
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-639.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00372 31st percentileScored 2026-11-07
Fix Fixed deepseek-mcp-server (arikusi): 1.7.0@arikusi/deepseek-mcp-server (npm): 1.7.0

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
arikusideepseek-mcp-server1.4.2 to before 1.7.01.7.0Patch availableCNA
—@arikusi/deepseek-mcp-server (npm)1.4.2 to before 1.7.01.7.0Patch availableGHSA-fh3r-g96v-f578
  • deepseek-mcp-server Vendorarikusi Affected 1.4.2 to before 1.7.0 Fixed in 1.7.0 Patch available CNA
  • @arikusi/deepseek-mcp-server (npm) Vendor— Affected 1.4.2 to before 1.7.0 Fixed in 1.7.0 Patch available GHSA-fh3r-g96v-f578

Remediation

  • Fix · CNA deepseek-mcp-server (arikusi) Fixed in 1.7.0
  • Fix · GHSA-fh3r-g96v-f578 @arikusi/deepseek-mcp-server (npm) Fixed in 1.7.0 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-55604
  2. 2026-10-03 Alias added: GHSA-fh3r-g96v-f578

References

Advisory 1

Other 3

  • TI-2026-40139 @arikusi/deepseek-mcp-server Missing Authentication on Self-Hosted HTTP MCP Endpoint CVSS 3.1MEDIUM 5.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences