CyberRota Analysis
AI-GeneratedThe RMCP Rust SDK prior to version 2.0.0 contains a vulnerability in its OAuth implementation that allows a malicious Model Context Protocol (MCP) server to manipulate resource metadata, potentially leading to unauthorized access tokens being issued to victims. This flaw enables attackers to impersonate users against legitimate MCP resources, exploiting the granted scopes of the access tokens. Organizations utilizing the RMCP SDK should prioritize upgrading to version 2.0.0 to mitigate this high-severity risk.
Public Exploit Signal
A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.
Note: these links are listed for security research and verification purposes only.
Original NVD Description
RMCP is an official Rust SDK for the Model Context Protocol. Prior to 2.0.0, the rmcp crate's OAuth implementation in crates/rmcp/src/transport/auth.rs omits the RFC 9728 resource field from ResourceServerMetadata and allows discover_oauth_server_via_resource_metadata to use protected-resource metadata without confirming that the returned resource identifier exactly matches the configured MCP server. A malicious MCP server can publish metadata for a different legitimate MCP resource and its authorization server, causing a victim who connects and completes the authorization flow to obtain a legitimate access token that the client subsequently sends to the malicious server. The attacker can capture the token and impersonate the victim against the legitimate MCP resource within the token's granted scopes. This issue is fixed in version 2.0.0.