Security brief

Historical advisory: MCP Inspector proxy authentication flaw enabled code execution

REVIEW

The affected tool was MCP Inspector, not every application using the Model Context Protocol.

Published 29 Oct 2026 · Material update 9 Jul 2025 — last time the underlying evidence changed · Evidence: high

What happened

CVE-2025-49596 concerns missing authentication between MCP Inspector’s client and proxy. The reviewed advisory says versions below 0.14.1 could accept unauthenticated requests that launch MCP commands over stdio.

MCP Inspector is a development and debugging tool. Exposure depends on running that affected tool and its reachable proxy; use of the MCP protocol alone does not establish applicability.

The advisory identifies 0.14.1 as the historical fixed release. Review developer tooling as well as production dependencies, and update affected installations to a supported patched release. This June 2025 disclosure is included as historical coverage, not a new breach claim.

Read the original source.

Who should check?

Developers running MCP Inspector below 0.14.1.

Next step

Update affected Inspector installations and review proxy exposure.

What we know

Historical fixed version
0.14.1

What remains unknown

Open question
The sources reviewed do not establish whether your deployment was exploited.

Source references

Technical details

CVE
CVE-2025-49596