CVE-2025-62801 json
FastMCP vulnerable to windows command injection in FastMCP Cursor installer via server_name
published 2025-10-28 12 mo ago modified 2026-10-08 31 d ago also GHSA-rj5c-58rq-j5g5 , PYSEC-2026-1365 , EUVD-2025-36567
- cvss
- 7.8
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 13%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- pypi fastmcp 2.13.0
- jlowin fastmcp 2.13.0
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- total
- Assessed
- 12 mo ago
Exploit prediction
0.23% chance of exploitation in the next 30 days, higher than 13% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/jlowin/fastmcp/security/advisories/GHSA-rj5c-58rq-j5g5 referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 5.4 | CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| CNA | 4.0 | 5.4 | CVSS: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 |
| NVD | 3.1 | 7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | fastmcp | <2.13.0 |
2.13.0 |
Affected products
- jlowin fastmcp
Classification
- Weakness
-
- CWE-78 Improper Neutralization of Special Elements used in an OS Command
References
-
github.com
/jlowin/fastmcp/security/advisories/GHSA-rj5c-58rq-j5g5
exploit, web, third-party-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2025-62801
advisory
-
github.com
/jlowin/fastmcp
package
-
pypi.org
/project/fastmcp
package
-
github.com
/advisories/GHSA-rj5c-58rq-j5g5
advisory
Sources
- CVE List CVE-2025-62801
- GitHub Advisory GHSA-rj5c-58rq-j5g5
- NVD CVE-2025-62801
- OSV PYSEC-2026-1365
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.