CVE-2025-66454 MEDIUM

CVE-2025-66454: Arcade MCP Default Hardcoded Worker Secret Allows Full Unauthorized Access to All HTTP MCP Worker Endpoints

Vendor Arcadeai
Product arcade-mcp
Weakness CWE-321
Published December 2, 2025
Last update December 2, 2025
View on NVD All CVEs

CVSS base score

6.5/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality Low
Integrity Low

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

December 2, 2025 CVE published
December 2, 2025 Record updated