CVE•Published 2026-05-14•Modified 2026-05-14•1 article on news•6 live references•NVD data
CVE-2026-42559
Vulnerability data via NVD (ingested)
CVSS v3.1
8.8
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS percentile
—
Weaknesses (CWE)
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.
Timeline
Published 2026-05-14
Modified 2026-05-14
External references
Search for exposed instances
Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).
More intel sources (5)
Shodan report
vuln:CVE-2026-42559Country / ASN / product breakdown for the vuln query.
Censys
vulnerabilities.cve_id: CVE-2026-42559Censys host search filtered to this CVE id.
grep.app
CVE-2026-42559Public source-code mentions — fast PoC discovery.
GitHub code
CVE-2026-42559GitHub code search for direct mentions.
Google dork
"CVE-2026-42559" exploit -site:nvd.nist.govWrite-ups and news, NVD excluded.