EUVD-2026-32672
GHSA-7pf3-8xx7-rvhf
CVSS VectorNVD
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
Lifecycle Timeline
4DescriptionNVD
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.
AnalysisAI
Cross-origin data exposure in Google's MCP Toolbox for Databases stems from the SSE initialization handler unconditionally emitting an Access-Control-Allow-Origin: * header, which overrides the allowed-origins/allowed-hosts controls added during beta and opens the endpoint to DNS rebinding. Any deployment using the SSE transport under MCP specification v2024-11-05 is affected, letting a remote attacker who lures a victim to a malicious web page read the victim's Toolbox/database tool responses cross-origin. …
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RemediationAI
Within 24 hours: Inventory all Google MCP Toolbox for Databases deployments using SSE transport (MCP spec v2024-11-05) and restrict network access to trusted sources only. Within 7 days: Monitor Google's security advisory channels and MCP project repositories for patch release following PR #3054; prepare update procedures in non-production labs. …
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