googleapis/mcp-toolbox · Security
MCP Toolbox for Databases vulnerable to DNS rebinding attacks
- GHSA ID
- GHSA-7pf3-8xx7-rvhf
- CVE ID
- CVE-2026-9739
- Severity
- critical
- Published
- Updated
- CVSS v4
- 9.4 · 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
Description
Vulnerable to DNS rebinding attacks when using SSE (http://b/499408790). During the beta phase, we implemented allowed-origins and allowed-hosts flags to align with MCP security guidelines. However, the hardcoded Access-Control-Allow-Origin: * header in the SSE initialization handler was inadvertently retained. This vulnerability specifically impacts users connecting via Toolbox using SSE under specification v2024-11-05.
CWEs
- CWE-942 · Permissive Cross-domain Security Policy with Untrusted Domains