CVE-2026-11624
CriticalCVSS 9.4Exploitation Probability (EPSS)
Low risk5th percentile - higher than 5% of all known CVEs
Summary
Model Context Protocol (MCP) before version 0.25.0 lacked Origin header validation to prevent DNS rebinding attacks. Version 0.25.0 introduces the --allowed-hosts flag, which defaults to '*' and warns about potential vulnerabilities.
Risk Assessment
Risk of DNS rebinding attacks that could allow an attacker to hijack sessions or access protected MCP server resources.
Recommendation
Upgrade Model Context Protocol to version 0.25.0 or later and configure the --allowed-hosts and --allowed-origins flags according to security requirements.
Original NVD description (English source)
The Model Context Protocol has a security warning advising servers to validate the "Origin" header on all incoming connections to prevent DNS rebinding attacks. Prior to the v0.25.0 release, users had no way to validate the origin's host. In v0.25.0, a new "--allowed-hosts" flag was introduced alongside the existing "--allowed-origins" flag, enabling users to specify permitted hosts at server startup. Both flags default to "*", allowing users to implement strict access controls as needed without breaking existing setups. If either flag is set to "*", the server will output a startup warning about potential vulnerabilities. Documentation has also been updated to highlight these security considerations.