MEDIUM 5.3 GitHub
CVE-2026-55605
@arikusi/deepseek-mcp-server: Missing Authentication on Self-Hosted HTTP MCP Endpoint
## Summary
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 `deeps
Affected Products
- npm/@arikusi/deepseek-mcp-server >= 1.4.2, < 1.8.0
References
- https://github.com/advisories/GHSA-72f3-6w86-7rv3
- https://github.com/arikusi/deepseek-mcp-server/security/advisories/GHSA-72f3-6w86-7rv3
- https://nvd.nist.gov/vuln/detail/CVE-2026-55605
- https://github.com/arikusi/deepseek-mcp-server/pull/4
This medium severity vulnerability with a CVSS score of 5.3 was published on 2026-08-25 via GitHub. Affected: npm/@arikusi/deepseek-mcp-server >= 1.4.2, < 1.8.0.
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