{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-11717: An authentication bypass vulnerability exists in the generic opaque token validation path (validateOpaqueToken) of googleapis/mcp-toolbox","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-11717","status":"final","version":"1","initial_release_date":"2026-06-18T11:50:23.665Z","current_release_date":"2026-06-18T12:23:15.209Z","revision_history":[{"date":"2026-06-18T11:50:23.665Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"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.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-11717 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-11717"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-11717"},{"category":"external","summary":"github.com","url":"https://github.com/googleapis/mcp-toolbox/pull/3341"}]},"product_tree":{"branches":[{"category":"vendor","name":"Google","branches":[{"category":"product_name","name":"MCP Toolbox for Databases (googleapis/mcp-toolbox)","branches":[{"category":"product_version_range","name":">=1.0.0 <=1.3.0","product":{"name":"Google MCP Toolbox for Databases (googleapis/mcp-toolbox) >=1.0.0 <=1.3.0","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:google:mcp_toolbox_for_databases_\\(googleapis\\/mcp-toolbox\\):*:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-11717","title":"An authentication bypass vulnerability exists in the generic opaque token validation path (validateOpaqueToken) of googleapis/mcp-toolbox","notes":[{"category":"description","text":"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.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1"]},"scores":[{"cvss_v4":{"version":"4.0","vectorString":"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","baseScore":9.3,"baseSeverity":"CRITICAL"},"products":["CSAFPID-1"]}],"remediations":[{"category":"none_available","details":"No fixed version is published yet. Monitor the upstream advisory.","product_ids":["CSAFPID-1"]}]}]}