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High, CVSS 8.6amended

MCP Inspector is Vulnerable to Potential Command Execution via XSS When Connecting to an Untrusted MCP Server

CVE-2025-58444GHSA-g9hg-qhmf-q45m

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (@modelcontextprotocol/inspector 0.16.6), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
8.6 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N · score source
EPSS
  • CVE-2025-58444: 0.70% estimated exploitation activity in the next 30 days; percentile 53.40 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

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, <superboyzjc@gmail.com & Shuyang Wang, <swang@obsidiansecurity.com.

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 3 · amended ·

    Amended from ghsa record GHSA-g9hg-qhmf-q45m

  2. Revision 2 · amended ·

    Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

  3. Revision 1 · created ·

    Published from osv record GHSA-g9hg-qhmf-q45m

Agent brief

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2025-58444

Advisory: MCP Inspector is Vulnerable to Potential Command Execution via XSS When Connecting to an Untrusted MCP Server
IDs: CVE-2025-58444, GHSA-g9hg-qhmf-q45m
Record: https://patchnext.com/advisories/cve-2025-58444 (revision 3, source checked 26 Oct 2026, 12:38 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: @modelcontextprotocol/inspector 0.16.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm @modelcontextprotocol/inspector: affected < 0.16.6; fixed in 0.16.6

## Suggested inspection (read-only)
- `npm ls @modelcontextprotocol/inspector --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on @modelcontextprotocol/inspector.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-g9hg-qhmf-q45m (OSV record GHSA-g9hg-qhmf-q45m lists affected ranges: npm @modelcontextprotocol/inspector >=0 <0.16.6 (fixed))
- Verified: https://github.com/advisories/GHSA-g9hg-qhmf-q45m (GitHub-reviewed advisory GHSA-g9hg-qhmf-q45m lists affected ranges: npm @modelcontextprotocol/inspector >=0 <0.16.6)

Commands are suggestions: review each one before running it.

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