CVE-2025-66454

02.12.2025, 19:15

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 endpointsincluding tool enumeration and tool invocationwithout credentials. This vulnerability is fixed in 1.5.4.

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	NIST	6.5 MEDIUM	NETWORK	LOW	NONE	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
GitHub_M	CNA	6.5 MEDIUM	NETWORK	LOW	NONE	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
CISA-ADP	ADP	---				---

Awaiting analysis

This vulnerability is currently awaiting analysis.

Base Score

CVSS 3.x

EPSS Score

Percentile: 36%

Common Weakness Enumeration

CWE-321 - Use of Hard-coded Cryptographic Key
The use of a hard-coded cryptographic key significantly increases the possibility that encrypted data may be recovered.

References

https://github.com/ArcadeAI/arcade-mcp/commit/44660d18ceb220600401303df860a31ca766c817

https://github.com/ArcadeAI/arcade-mcp/pull/691

https://github.com/ArcadeAI/arcade-mcp/security/advisories/GHSA-g2jx-37x6-6438