CVE-2025-66454
MEDIUMArcade MCP <1.5.4 - Auth Bypass
Title source: llmDescription
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.
Scores
CVSS v3
6.5
EPSS
0.0027
EPSS Percentile
50.3%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Classification
CWE
CWE-321
CWE-798
Status
draft
Affected Products (1)
pypi/arcade-mcp-server
< 1.9.1PyPI
Timeline
Published
Dec 02, 2025
Tracked Since
Feb 18, 2026