CVE-2026-42559— RMCP: DNS rebinding vulnerability in rmcp Streamable HTTP server transport
Possible ATT&CK Techniques 1AI
T1190 · Exploit Public-Facing ApplicationAffected Version Matrix 1
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| modelcontextprotocol | rust-sdk | < 1.4.0 | affected |
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I. Basic Information for CVE-2026-42559
Vulnerability Information
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Vulnerability Title
RMCP: DNS rebinding vulnerability in rmcp Streamable HTTP server transport
Source: NVD (National Vulnerability Database)
Vulnerability 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.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Source: NVD (National Vulnerability Database)
Vulnerability Type
源验证错误
Source: NVD (National Vulnerability Database)
Vulnerability Title
RMCP 访问控制错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
RMCP是Model Context Protocol开源的一个基于Tokio异步运行时的Rust模型上下文协议SDK实现。 RMCP 1.4.0之前版本存在访问控制错误漏洞，该漏洞源于Streamable HTTP服务器传输未验证传入的Host标头，可能导致恶意公共网站通过DNS重新绑定攻击向受害者回环或私有网络接口上运行的MCP服务器发送认证请求。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| modelcontextprotocol | rust-sdk | < 1.4.0 | - |
II. Public POCs for CVE-2026-42559
| # | POC Description | Source Link | Shenlong Link |
|---|
AI-Generated POCPremium
Qwen3.6-35B-A3B · 9888 chars
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III. Intelligence Information for CVE-2026-42559
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- https://github.com/modelcontextprotocol/rust-sdk/pull/764x_refsource_MISC
- https://github.com/modelcontextprotocol/rust-sdk/issues/822x_refsource_MISC
- https://github.com/modelcontextprotocol/rust-sdk/issues/815x_refsource_MISC
- https://nvd.nist.gov/vuln/detail/CVE-2026-42559
Same Patch Batch · modelcontextprotocol · 2026-05-14 · 6 CVEs total
| CVE-2026-45781 | 3.5 LOW | MCP Registry: OCI ownership validation fails open on upstream rate limits, allowing attack |
| CVE-2026-44429 | MCP Registry: Stored XSS in catalogue UI via attribute-quote breakout in publisher-control | |
| CVE-2026-44430 | MCP Registry: Unauthenticated SSRF: HTTP namespace verification dials 6to4 / NAT64 / site- | |
| CVE-2026-44427 | MCP Registry: Open Redirect | |
| CVE-2026-44428 | MCP Registry: GitHub OIDC tokens replayable across registry deployments due to shared audi |
IV. Related Vulnerabilities
Same vendor: modelcontextprotocol
- CVE-2026-44428
MCP Registry: GitHub OIDC tokens replayable across registry - CVE-2026-44427
MCP Registry: Open Redirect - CVE-2026-44429
MCP Registry: Stored XSS in catalogue UI via attribute-quote - CVE-2026-44430
MCP Registry: Unauthenticated SSRF: HTTP namespace verificat - CVE-2026-45781
MCP Registry: OCI ownership validation fails open on upstrea
Same weakness: CWE-346
V. Comments for CVE-2026-42559
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