CVE-2026-44427: Modelcontextprotocol Registry

None severity, CVSS 0.0. EPSS: 0.4% chance of exploitation in the next 30 days.

The MCP Registry provides MCP clients with a list of MCP servers, like an app store for MCP servers. From 1.1.0 to 1.7.4, the TrailingSlashMiddleware in internal/api/server.go is vulnerable to an open redirect attack. An attacker can craft a URL with a protocol-relative path (e.g., //evil.com/) that, after trailing slash removal, results in a Location header of //evil.com — which browsers interpret as an absolute URL to an external domain. This vulnerability is fixed in 1.7.5.

Affected products

• Modelcontextprotocol Registry: from 1.1.0, before 1.7.5 (fixed in 1.7.5)

Published 2026-05-14. Last modified 2026-06-17.