What is CVE-2025-66454?

CVE-2025-66454 is a medium-severity vulnerability in Arcadeai Arcade-Mcp, classified under Use of Hard-coded Cryptographic Key. CVSS score: 6.5/10. Published 2025-12-02.

How severe is CVE-2025-66454?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Arcadeai Arcade-Mcp

CVE-2025-66454

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.

EPSS: 0.003 (21.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.

Affected products

Arcadeai Arcade-mcp — versions < 1.5.4

Weakness classification (CWE)

References

security-advisories@github.com (x_refsource_CONFIRM)
security-advisories@github.com (x_refsource_MISC)
security-advisories@github.com (x_refsource_MISC)

Frequently asked questions

What is CVE-2025-66454?: CVE-2025-66454 is a medium-severity vulnerability in Arcadeai Arcade-Mcp, classified under Use of Hard-coded Cryptographic Key. CVSS score: 6.5/10. Published 2025-12-02.
How severe is CVE-2025-66454?: Medium severity. CVSS v3 base score is 6.5 out of 10.