CVE-2026-42559
8.8
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Exploitability: 2.8 / Impact: 5.9
Source: security-advisories@github.com (Secondary)
Description
RMCP is an official Rust SDK for the Model Context Protocol. Prior to version 1.4.0, the rmcp crate's Streamable HTTP server transport (crates/rmcp/src/transport/streamable_http_server/) did not validate the incoming Host header. This allowed a malicious public website, via a DNS rebinding attack, to send authenticated requests to an MCP server running on the victim's loopback or private-network interface. This vulnerability is fixed in 1.4.0.
Related CWEs
CWE-346
Origin Validation Error
The product does not properly verify that the source of data or communication is valid.
CWE-350
Reliance on Reverse DNS Resolution for a Security-Critical Action
The product performs reverse DNS resolution on an IP address to obtain the hostname and make a security decision, but it does not properly ensure that the IP address is truly associated with the hostname.
References (5)
Source: security-advisories@github.com
Source: security-advisories@github.com
Source: security-advisories@github.com
Source: security-advisories@github.com
Source: security-advisories@github.com
Timeline
No history available yet.