CVE-2025-66454
Arcade MCP Default Hardcoded Worker Secret Allows Full Unauthorized Access to All HTTP MCP Worker Endpoints
Description
Arcade MCP allows you to to create, deploy, and share MCP Servers. Prior to 1.5.4, the arcade-mcp HTTP server uses a hardcoded default worker secret ("dev") that is never validated or overridden during normal server startup. As a result, any unauthenticated attacker who knows this default key can forge valid JWTs and fully bypass the FastAPI authentication layer. This grants remote access to all worker endpoints—including tool enumeration and tool invocation—without credentials. This vulnerability is fixed in 1.5.4.
INFO
Published Date :
Dec. 2, 2025, 7:15 p.m.
Last Modified :
Oct. 18, 2026, 6:10 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] |
Solution
- Update Arcade MCP to version 1.5.4.
- Verify the worker secret is not the default value.
- Ensure JWTs are properly validated.
Public PoC/Exploit Available at Github
CVE-2025-66454 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
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-2025-66454.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-66454 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-2025-66454
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).
The Project shares all information on MCP related CVE's published
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Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-66454 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-66454 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. 18, 2026
Action Type Old Value New Value Added Translation Title: arcade-mcp de ArcadeAI, Description: Arcade MCP permite crear, desplegar y compartir servidores MCP. Versiones anteriores a 1.5.4, el servidor HTTP arcade-mcp utiliza un secreto de trabajador predeterminado codificado (“dev”) que nunca se valida ni se sobrescribe durante el inicio normal del servidor. Como resultado, cualquier atacante no autenticado que conozca esta clave predeterminada puede falsificar JWT válidos y eludir completamente la capa de autenticación de FastAPI. Esto otorga acceso remoto a todos los endpoints de trabajador -incluyendo la enumeración e invocación de herramientas- sin credenciales. Esta vulnerabilidad se ha corregido en la versión 1.5.4. -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'ArcadeAI', 'product': 'arcade-mcp', 'versions': [{'status': 'affected', 'version': '< 1.5.4'}]}] -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 17, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2025-66454', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2025-12-02T19:28:19.190064Z'} -
New CVE Received by [email protected]
Dec. 02, 2025
Action Type Old Value New Value Added Description Arcade MCP allows you to to create, deploy, and share MCP Servers. Prior to 1.5.4, the arcade-mcp HTTP server uses a hardcoded default worker secret ("dev") that is never validated or overridden during normal server startup. As a result, any unauthenticated attacker who knows this default key can forge valid JWTs and fully bypass the FastAPI authentication layer. This grants remote access to all worker endpoints—including tool enumeration and tool invocation—without credentials. This vulnerability is fixed in 1.5.4. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N Added CWE CWE-798 Added CWE CWE-321 Added Reference https://github.com/ArcadeAI/arcade-mcp/commit/44660d18ceb220600401303df860a31ca766c817 Added Reference https://github.com/ArcadeAI/arcade-mcp/pull/691 Added Reference https://github.com/ArcadeAI/arcade-mcp/security/advisories/GHSA-g2jx-37x6-6438