CVE-2025-62801

FastMCP vulnerable to windows command injection in FastMCP Cursor installer via server_name

FastMCP is the standard framework for building MCP applications. Versions prior to 2.13.0, a command-injection vulnerability lets any attacker who can influence the server_name field of an MCP execute arbitrary OS commands on Windows hosts that run fastmcp install cursor. This vulnerability is fixed in 2.13.0.

Affected

jlowin · fastmcp

CVSS v4.0 GITHUB

5.4 MEDIUMCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v4.0 GitHub

5.4 MEDIUMCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS v3.1 NVD

7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

0.23% chance of exploitation in the next 30 days, 13th percentile

Published

2025-10-28

Updated

2025-10-29

Proof-of-concept exploits (1)

• advisories/GHSA-rj5c-58rq-j5g5

Security advisories

• jlowin/fastmcp/security/advisories/GHSA-rj5c-58rq-j5g5

References

• CVE Record
• NVD entry