CVE-2026-42559

Published: Mag 14, 2026 Last Modified: Mag 14, 2026
ExploitDB:
Other exploit source:
Google Dorks:
HIGH 8,8
Attack Vector: network
Attack Complexity: low
Privileges Required: none
User Interaction: required
Scope: unchanged
Confidentiality: high
Integrity: high
Availability: high

Description

AI Translation Available

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.

EPSS (Exploit Prediction Scoring System)

Trend Analysis

EPSS (Exploit Prediction Scoring System)

Prevede la probabilità di sfruttamento basata su intelligence sulle minacce e sulle caratteristiche della vulnerabilità.

EPSS Score
0,0002
Percentile
0,0th
Updated

EPSS Score Trend (Last 6 Days)

346

Origin Validation Error

Draft
Common Consequences
Security Scopes Affected:
Access Control Other
Potential Impacts:
Gain Privileges Or Assume Identity Varies By Context
Applicable Platforms
Technologies: Not Technology-Specific, Web Based
View CWE Details
350

Reliance on Reverse DNS Resolution for a Security-Critical Action

Draft
Common Consequences
Security Scopes Affected:
Access Control
Potential Impacts:
Gain Privileges Or Assume Identity Bypass Protection Mechanism
Applicable Platforms
All platforms may be affected
View CWE Details
https://github.com/modelcontextprotocol/rust-sdk/commit/8e22aa2de28df5a285eed87…
https://github.com/modelcontextprotocol/rust-sdk/issues/815
https://github.com/modelcontextprotocol/rust-sdk/issues/822
https://github.com/modelcontextprotocol/rust-sdk/pull/764
https://github.com/modelcontextprotocol/rust-sdk/security/advisories/GHSA-89vp-…