CVEvulnerability

CVE-2026-42559

8.8 HIGH Published 2026-05-14 Modified 2026-10-26 Official page ↗
Status
Deferred
Published
2026-05-14
Last modified
2026-10-26
Assigner
[email protected]
CVSS 3.1 ([email protected])
8.8 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weaknesses
CWE-346, CWE-350

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

Weakness · CWE (2)

  • CWE-346 Origin Validation Error weakness
  • CWE-350 Reliance on Reverse DNS Resolution for a Security-Critical Action weakness

References