{"cve":"CVE-2026-9739","nvd":{"published":"2026-05-27T23:16:48.573","modified":"2026-10-26T12:10:00.130","status":"Awaiting Analysis","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.","cvss_v4":{"vector":"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","score":9.4},"cvss_v3":null,"cwes":["CWE-942"],"references":["https://github.com/googleapis/mcp-toolbox/issues/3053","https://github.com/googleapis/mcp-toolbox/pull/3054"],"products":[],"source":"nvd","synced_at":"2026-10-26T12:35:18.182177120+00:00"},"epss":{"cve":"CVE-2026-9739","score":0.00279,"percentile":0.20186,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-7pf3-8xx7-rvhf","url":"https://osv.dev/vulnerability/GHSA-7pf3-8xx7-rvhf","summary":"MCP Toolbox for Databases vulnerable to DNS rebinding attacks","modified":"2026-07-07T16:11:35.449476804Z","packages":[{"ecosystem":"Go","name":"github.com/googleapis/mcp-toolbox","purl":"pkg:golang/github.com/googleapis/mcp-toolbox","ranges":["<1.2.0"],"fixed":["1.2.0"]}]},{"id":"GO-2026-5870","url":"https://osv.dev/vulnerability/GO-2026-5870","summary":"MCP Toolbox for Databases vulnerable to DNS rebinding attacks in github.com/googleapis/mcp-toolbox","modified":"2026-07-07T16:01:31.265715365Z","packages":[{"ecosystem":"Go","name":"github.com/googleapis/mcp-toolbox","purl":"pkg:golang/github.com/googleapis/mcp-toolbox","ranges":["<1.2.0"],"fixed":["1.2.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}