FastMCP has a Command Injection vulnerability - Gemini CLI (jlowin fastmcp)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.75 % · percentile 55 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Analyzed
Description
FastMCP is the standard framework for building MCP applications. Prior to version 3.2.0, server names containing shell metacharacters (e.g., &) can cause command injection on Windows when passed to fastmcp install claude-code or fastmcp install gemini-cli. These install paths use subprocess.run() with a list argument, but on Windows the target CLIs often resolve to .cmd wrappers that are executed through cmd.exe, which interprets metacharacters in the flattened command string. This issue has been patched in version 3.2.0.
Weaknesses (CWE)
- CWE-78 — Improper Neutralization of Special Elements used in an OS Command
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 6.7 | CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H | GitHub_M |
| CVSS 3.1 | MEDIUM 6.7 | CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H | NVD · security-advisories@github.com (Secondary) |
| CVSS 3.1 | HIGH 7.8 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H | NVD · nvd@nist.gov (Primary) |
Advisories
- GHSA-m8x7-r2rg-vh5g — FastMCP has a Command Injection vulnerability - Gemini CLI
- PYSEC-2026-2475 — FastMCP has a Command Injection vulnerability - Gemini CLI
European references
- ENISA EUVD · EUVD-2025-209207
- GCVE · GCVE-0-2025-64340
CERT-FR advisories
- CERTFR-2026-AVI-0550 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:jlowin:fastmcp:*:*:*:*:*:*:*:*< 3.2.0
Affected products
| Product | Versions |
|---|---|
| jlowin · fastmcp | affected < 3.2.0 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |