CVE-2025-66454
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-12-02

Last updated on: 2025-12-02

Assigner: GitHub, Inc.

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.
CVSS Scores
EPSS Scores
Probability:
Percentile:
Meta Information
Published
2025-12-02
Last Modified
2025-12-02
Generated
2026-06-16
AI Q&A
2025-12-02
EPSS Evaluated
2026-06-14
NVD
CVE-2025-66454
EUVD
EUVD-2025-200280
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
arcade_mcp arcade_mcp *
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-321 The product uses a hard-coded, unchangeable cryptographic key.
CWE-798 The product contains hard-coded credentials, such as a password or cryptographic key.
Attack-Flow Graph
AI Quick Actions
Instant insights powered by AI
Executive Summary

The vulnerability in Arcade MCP prior to version 1.5.4 is due to the HTTP server using a hardcoded default worker secret "dev" that is never validated or overridden during normal server startup. This allows any unauthenticated attacker who knows this default key to forge valid JWTs and bypass the FastAPI authentication layer, gaining remote access to all worker endpoints without credentials.

Impact Analysis

This vulnerability can allow an attacker to remotely access all worker endpoints of the Arcade MCP server without any credentials. This includes the ability to enumerate and invoke tools, potentially leading to unauthorized actions and data exposure.

Mitigation Strategies

Upgrade the arcade-mcp HTTP server to version 1.5.4 or later, where the hardcoded default worker secret is removed and properly validated. Until then, avoid using the default worker secret "dev" to prevent unauthorized JWT forgery and bypass of authentication.

Chat Assistant
Ask questions about this CVE
Hi! I’m here to help you understand CVE-2025-66454. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70
EPSS Chart