Description
MCP Ruby SDK is the official Ruby SDK for Model Context Protocol servers and clients. Prior to 0.23.0, MCP::Server::Transports::StreamableHTTPTransport in the mcp gem does not validate the HTTP Host or Origin request headers, which allows a malicious browser page to use DNS rebinding to reach a locally running MCP server and invoke exposed tools. This issue is fixed in version 0.23.0.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| modelcontextprotocol | ruby-sdk | < 0.23.0 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| RubyGems | mcp | < 0.23.0 | 0.23.0 | GHSA-rjr6-rcgv-9m7m |