{"cve":"CVE-2026-11717","nvd":{"published":"2026-06-18T14:17:20.013","modified":"2026-10-26T11:10:00.157","status":"Analyzed","description":"An authentication bypass vulnerability exists in the generic opaque token validation path (validateOpaqueToken) of googleapis/mcp-toolbox.\n\nWhen verifying an unparsed opaque token via an OAuth 2.0 introspection endpoint (RFC 7662), the toolbox decodes the response into an introspectResp struct where the Active field is declared as a pointer to a boolean (*bool). The code only explicitly rejects a token if the response contains a populated active field set to false (if introspectResp.Active != nil && !*introspectResp.Active). If an introspection endpoint responds with a payload that completely omits the mandatory active key, the internal variable remains nil, causing the conditional check to short-circuit. As a result, Toolbox accepts authorization tokens missing the \"active\" field, granting access to protected tools and underlying data sources.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","score":9.3},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","score":9.1},"cwes":["CWE-287"],"references":["https://github.com/googleapis/mcp-toolbox/pull/3341"],"products":["google:mcp_toolbox_for_databases"],"source":"nvd","synced_at":"2026-10-26T11:33:08.859761529+00:00"},"epss":{"cve":"CVE-2026-11717","score":0.00176,"percentile":0.07114,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-8fcc-w5hv-4gxv","url":"https://osv.dev/vulnerability/GHSA-8fcc-w5hv-4gxv","summary":"googleapis/mcp-toolbox: authentication bypass vulnerability in the generic opaque token validation path (validateOpaqueToken)","modified":"2026-06-25T19:56:37.781543822Z","packages":[{"ecosystem":"Go","name":"github.com/googleapis/mcp-toolbox","purl":"pkg:golang/github.com/googleapis/mcp-toolbox","ranges":["<1.4.0"],"fixed":["1.4.0"]}]},{"id":"GO-2026-5251","url":"https://osv.dev/vulnerability/GO-2026-5251","summary":"googleapis/mcp-toolbox: authentication bypass vulnerability in the generic opaque token validation path (validateOpaqueToken) in github.com/googleapis/mcp-toolbox","modified":"2026-06-25T19:45:20.063614668Z","packages":[{"ecosystem":"Go","name":"github.com/googleapis/mcp-toolbox","purl":"pkg:golang/github.com/googleapis/mcp-toolbox","ranges":["<1.4.0"],"fixed":["1.4.0"]}]}],"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."]}