Microsoft Playwright MCP Server versions prior to 0.0.40 fails to validate the Origin header on incoming connections.
Date: 2026-01
Attack vector: other
Category: vulnerability-disclosure
Severity: Medium
CVE: CVE-2025-9611
CWE: CWE-749

Microsoft Playwright MCP Server versions prior to 0.0.40 fails to validate the Origin header on incoming connections. This allows an attacker to perform a DNS rebinding attack via a victim’s web browser and send unauthorized requests to a locally running MCP server, resulting in unintended invocation of MCP tool endpoints.


Mitigations:

Architectural layers (MAESTRO):