GHSA-g9hg-qhmf-q45m — @modelcontextprotocol/ins…
Fix: modelcontextprotocol/inspector@650f309GHSA-g9hg-qhmf-q45m is a CWE-84 vulnerability in @modelcontextprotocol/inspector. A fix is available for @modelcontextprotocol/inspector — see the affected versions and patch details below.
MCP Inspector is Vulnerable to Potential Command Execution via XSS When Connecting to an Untrusted MCP Server
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-g9hg-qhmf-q45m.
EPSS Exploitation Probability
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
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@modelcontextprotocol/inspectornpmDescription
An XSS flaw exists in the MCP Inspector local development tool when it renders a redirect URL returned by a remote MCP server. If the Inspector connects to an untrusted server, a crafted redirect can inject script into the Inspector context and, via the built-in proxy, be leveraged to trigger arbitrary command execution on the developer machine. Version 0.16.6 hardens URL handling/validation and prevents script execution.
Thank you to the following researchers for their reports and contributions:
- Raymond (Veria Labs)
- Gavin Zhong, [email protected] & Shuyang Wang, [email protected].
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @modelcontextprotocol/inspector | all versions | 0.16.6npm install @modelcontextprotocol/inspector@0.16.6 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @modelcontextprotocol/inspector, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @modelcontextprotocol/inspector to 0.16.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g9hg-qhmf-q45m is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-g9hg-qhmf-q45m can be triaged on real exposure rather than presence alone.
Tailored to GHSA-g9hg-qhmf-q45m. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-g9hg-qhmf-q45m in your dependencies?
O3 Security finds GHSA-g9hg-qhmf-q45m across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.