CVE-2026-55605
@arikusi/deepseek-mcp-server Missing Authentication on Self-Hosted HTTP MCP Endpoint
Description
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.
INFO
Published Date :
July 9, 2026, 10:17 p.m.
Last Modified :
Oct. 25, 2026, 5:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE |
Solution
- Update to version 1.8.0 or later.
- Ensure proper authentication for the HTTP transport.
- Restrict network access to the MCP server.
- Review and secure API key usage.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-55605.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-55605 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-55605
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-55605 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-55605 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 25, 2026
Action Type Old Value New Value Added Translation Title: deepseek-mcp-server de arikusi, Description: DeepSeek MCP Server es un servidor MCP para DeepSeek V4. A partir de la versión 1.4.2 y antes de la versión 1.8.0, el transporte HTTP autoalojado de “@arikusi/deepseek-mcp-server” expone “POST /mcp” sin ninguna autenticación: “createMcpExpressApp” se llama sin un “authProvider” y ningún middleware protege la ruta, por lo que cualquier cliente accesible por red puede emitir una solicitud “initialize” no autenticada y obtener un identificador de sesión MCP válido. En pruebas reproducidas contra el commit “5e1302171e99”, un cliente no autenticado pudo inicializar una sesión, enumerar herramientas e invocar la herramienta local “deepseek_sessions” sin credenciales. La misma sesión no autenticada también expone “deepseek_chat”, cuyo gestor utiliza la “DEEPSEEK_API_KEY” del lado del servidor cuando las implementaciones autoalojadas configuran una. Este problema se aplica al modo HTTP autoalojado, no al endpoint BYOK alojado documentado por separado en “README.md”, que espera un encabezado “Authorization: Bearer ...”. Los activos de contenedor autoalojados upstream habilitan el modo HTTP por defecto (“Dockerfile”) y publican el puerto “3000” (“docker-compose.yml”). La versión 1.8.0 contiene un parche para este problema. -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 10, 2026
Action Type Old Value New Value Added Reference https://github.com/arikusi/deepseek-mcp-server/security/advisories/GHSA-72f3-6w86-7rv3 Added SSVC {'id': 'CVE-2026-55605', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-10T13:35:04.651716Z'} -
New CVE Received by [email protected]
Jul. 09, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'arikusi', 'product': 'deepseek-mcp-server', 'versions': [{'status': 'affected', 'version': '>= 1.4.2, < 1.8.0'}]}] Added Description 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Added CWE CWE-306 Added Reference https://github.com/arikusi/deepseek-mcp-server/blob/main/CHANGELOG.md#180---2026-06-14 Added Reference https://github.com/arikusi/deepseek-mcp-server/releases/tag/v1.8.0 Added Reference https://github.com/arikusi/deepseek-mcp-server/security/advisories/GHSA-72f3-6w86-7rv3