How severe is CVE-2025-62801?

No CVSS score has been assigned to CVE-2025-62801 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2025-62801?

CVE-2025-62801 affects the following packages: fastmcp (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2025-62801?

Update fastmcp to 2.13.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-62801 is resolved across your whole dependency graph.

How do I detect CVE-2025-62801 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fastmcp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-62801 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2025-62801?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-62801 can be triaged on real exposure rather than presence alone.

Is CVE-2025-62801 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-62801 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-62801?

CVE-2025-62801 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 12th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2025-62801 published, and has it been updated?

CVE-2025-62801 was published on October 28, 2025 and was last updated on August 27, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2025-62801 — fastmcp

CVE-2025-62801 is a security vulnerability in fastmcp. A fix is available for fastmcp — see the affected versions and patch details below.

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

Also known asGHSA-rj5c-58rq-j5g5PYSEC-2026-1365

Published

Oct 28, 2025

Updated

Aug 27, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 19, 2026 · OSV.dev, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-62801.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs12th percentile — riskier than 12% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

1 pkg affected

🐍fastmcp

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

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 Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`fastmcp`	all versions	2.13.0`pip install --upgrade 'fastmcp==2.13.0'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for fastmcp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update fastmcp to 2.13.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-62801 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-62801 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2025-62801. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2025-62801 in your dependencies?

O3 Security finds CVE-2025-62801 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works