Medium 5.3Published Jul 9, 2026

CVE-2026-55605@arikusi/deepseek-mcp-server Missing Authentication on Self-Hosted HTTP MCP Endpoint

Updated under an hour ago (Oct 27, 2026, 8:25 PM ET)

Does this affect you?

It affects arikusi deepseek-mcp-server. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Do this next

Start free and add your stack

Free account, 1 product

Every CVE for arikusi deepseek-mcp-server

Exploited in the last 30 days

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.

CVSS: 5.3 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness (CWE): CWE-306
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Jul 10, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

arikusi deepseek-mcp-server arikusi:deepseek_mcp_server (from the name)	from 1.4.2, < 1.8.0	CNA record

References

References

https://github.com/arikusi/deepseek-mcp-server/security/advisories/GHSA-72f3-6w86-7rv3	x-refsource-confirm
https://github.com/arikusi/deepseek-mcp-server/blob/main/CHANGELOG.md#180---2026-06-14	x-refsource-misc
https://github.com/arikusi/deepseek-mcp-server/releases/tag/v1.8.0	x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.