CVE-2026-9739
28Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 9.4epss 0.3%
exploitation probability
0.3%top 80% of all CVEs
observed exploitation
nono source reports it
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.
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
Affected products
Google · MCP Toolbox for Databases