{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-14541","assignerOrgId":"14ed7db2-1595-443d-9d34-6215bf890778","state":"PUBLISHED","assignerShortName":"Google","dateReserved":"2026-07-03T03:38:02.749Z","datePublished":"2026-07-31T01:48:39.019Z","dateUpdated":"2026-07-31T16:14:54.005Z"},"containers":{"cna":{"providerMetadata":{"orgId":"14ed7db2-1595-443d-9d34-6215bf890778","shortName":"Google","dateUpdated":"2026-07-31T01:48:39.019Z"},"title":"Authentication Bypass and Audience Confusion in MCP Toolbox OAuth Provider","problemTypes":[{"descriptions":[{"lang":"en","cweId":"CWE-287","description":"CWE-287 (Improper Authentication)","type":"CWE"}]}],"impacts":[{"capecId":"CAPEC-115","descriptions":[{"lang":"en","value":"CAPEC-115 Authentication Bypass"}]}],"affected":[{"vendor":"Google","product":"mcp-toolbox","versions":[{"status":"affected","version":"1.4.0","versionType":"semver"}],"defaultStatus":"unaffected"}],"descriptions":[{"lang":"en","value":"An authentication bypass and audience confusion vulnerability exists in the Google OAuth provider component of Google mcp-toolbox version 1.4.0. When a Google authService is initialized with mcpEnabled: true but lacks an explicitly defined audience or clientId, the ValidateMCPAuth pipeline for opaque tokens skips audience validation entirely. As a result, the toolbox will accept any valid Google OAuth access token—even those minted for unrelated ecosystem applications—granting unauthorized clients access to protected tools and data backends.","supportingMedia":[{"type":"text/html","base64":false,"value":"An authentication bypass and audience confusion vulnerability exists in the Google OAuth provider component of Google mcp-toolbox version 1.4.0. When a Google authService is initialized with mcpEnabled: true but lacks an explicitly defined audience or clientId, the ValidateMCPAuth pipeline for opaque tokens skips audience validation entirely. As a result, the toolbox will accept any valid Google OAuth access token—even those minted for unrelated ecosystem applications—granting unauthorized clients access to protected tools and data backends."}]}],"references":[{"url":"https://github.com/googleapis/mcp-toolbox/pull/3450"}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","subConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","subIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"UNREPORTED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED","version":"4.0","baseSeverity":"HIGH","baseScore":8,"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/E:U"}}],"credits":[{"lang":"en","value":"HE WEI (ギカク)","type":"finder"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.2"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-31T16:14:40.882881Z","id":"CVE-2026-14541","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-07-31T16:14:54.005Z"}}]}}