PT-2026-56972 · Arikusi · Deepseek-Mcp-Server

Published 2026-07-09 · Updated 2026-07-09 · CVE-2026-55605

NVD

CVSS v3.1

5.3

Medium

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

DeepSeek MCP Server is an MCP server for DeepSeek V4. Starting in version 1.4.2 and prior to version 1.8.0, the self-hosted HTTP transport of @arikusi/deepseek-mcp-server exposes POST /mcp without any authentication: createMcpExpressApp is called without an authProvider and no middleware guards the route, so any network-reachable client can issue an unauthenticated initialize request and obtain a valid MCP session identifier. In reproduced testing against commit 5e1302171e99, an unauthenticated client was able to initialize a session, enumerate tools, and invoke the local deepseek sessions tool with no credentials. The same unauthenticated session also exposes deepseek chat, whose handler uses the server-side DEEPSEEK API KEY when self-hosted deployments configure one. This issue applies to self-hosted HTTP mode, not the separately documented hosted BYOK endpoint in README.md, which expects an Authorization: Bearer ... header. Upstream self-hosted container assets enable HTTP mode by default (Dockerfile) and publish port 3000 (docker-compose.yml). Version 1.8.0 contains a patch for this issue.

Fix

Missing Authentication

Weakness Enumeration

CWE-306

Related Identifiers

CVE-2026-55605

Affected Products

Deepseek-Mcp-Server

References · 4

• https://nvd.nist.gov/vuln/detail/CVE-2026-55605 · Security Note
• https://github.com/arikusi/deepseek-mcp-server/blob/main/CHANGELOG.md#180---2026-06-14 · Note
• https://github.com/arikusi/deepseek-mcp-server/releases/tag/v1.8.0 · Note
• https://github.com/arikusi/deepseek-mcp-server/security/advisories/GHSA-72f3-6w86-7rv3 · Note