CVE-2026-11624

CRITICAL EPSS 4.8%

Published Jun 13, 20263w ago · Modified Jun 17, 20262w ago

9.4 CVSS 4.0

Critical

Published Jun 13, 2026 3w ago

Last Modified Jun 17, 2026 2w ago

Description

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.

CVSS Details

Base Score

9.4

Exploitability

—

Impact

—

Vector string

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector Network

Attack Complexity Low

Privileges Required None

User Interaction A

Scope X

Threat Intelligence

EPSS Exploit Probability

4.8% percentile

Exploit & Patch Status

No Known Exploit

No Patch Available

Weaknesses 1

CWE-346

References 2

github.com https://github.com/googleapis/mcp-toolbox/issues/3113
github.com https://github.com/googleapis/mcp-toolbox/pull/2254

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.