CVE-2025-66454
Medium
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.
SeverityMedium
CVSS6.5
Exploit probability—
ProductArcade-mcp-server
PublishedDec 2, 2025
First seenDec 2, 2025
Weakness typeCWE-321CWE-321CWE-798Hard-coded credentials
How to fix
Update
- arcade-mcp-server1.9.1 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| arcade-mcp-serverPyPI | v < 1.9.1 | 1.9.1 |
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