CVE-2025-66390

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{"affected": [{"affectedData": [{"product": "n/a", "vendor": "n/a", "versions": [{"status": "affected", "version": "n/a"}]}], "source": "cve@mitre.org"}], "cveTags": [{"sourceIdentifier": "cve@mitre.org", "tags": ["disputed"]}], "descriptions": [{"lang": "en", "value": "In Microsoft Azure API Management through 2025-10-17, when self-service signup (username/password Basic Authentication) is enabled in Tenant A, an attacker can reuse the registration flow by changing the hostname or tenant identifier to Tenant B, even when Tenant B has signup disabled at the UI level. In other words, disabling signup in the UI does not disable the underlying API endpoint (which still accepts cross-tenant requests based on the Host header). NOTE: The supplier states that they evaluated the report and determined it did not cross a security boundary (i.e., the observed behavior was a configuration/state issue rather than an exploitable product vulnerability affecting tenant isolation). NOTE: The supplier evaluated this report and determined that it did not cross a security boundary (i.e., the observed behavior was a configuration/state issue rather than an exploitable product vulnerability affecting tenant isolation)."}, {"lang": "es", "value": "En Microsoft Azure API Management hasta el 17-10-2025, cuando el registro de autoservicio (autenticaci\u00f3n b\u00e1sica de nombre de usuario/contrase\u00f1a) est\u00e1 habilitado en el Inquilino A, un atacante puede reutilizar el flujo de registro cambiando el nombre de host o el identificador de inquilino al Inquilino B, incluso cuando el Inquilino B tiene el registro deshabilitado a nivel de la interfaz de usuario. En otras palabras, deshabilitar el registro en la interfaz de usuario no deshabilita el endpoint de la API subyacente (que a\u00fan acepta solicitudes entre inquilinos basadas en el encabezado Host). NOTA: El proveedor afirma que evaluaron el informe y determinaron que no cruzaba un l\u00edmite de seguridad (es decir, el comportamiento observado fue un problema de configuraci\u00f3n/estado en lugar de una vulnerabilidad de producto explotable que afectara el aislamiento de inquilinos). NOTA: El proveedor evalu\u00f3 este informe y determin\u00f3 que no cruzaba un l\u00edmite de seguridad (es decir, el comportamiento observado fue un problema de configuraci\u00f3n/estado en lugar de una vulnerabilidad de producto explotable que afectara el aislamiento de inquilinos)."}], "id": "CVE-2025-66390", "lastModified": "2026-10-12T19:10:00.217", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2025-66390", "options": [{"exploitation": "poc"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-07-22T15:18:22.488125Z", "version": "2.0.3"}}]}, "published": "2026-07-21T14:16:32.797", "references": [{"source": "cve@mitre.org", "url": "https://github.com/bountyyfi/Azure-APIM-Cross-Tenant-Signup-Bypass"}, {"source": "cve@mitre.org", "url": "https://github.com/bountyyfi/Azure-APIM-Cross-Tenant-Signup-Bypass/security/advisories/GHSA-vcwf-73jp-r7mv"}, {"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "url": "https://github.com/bountyyfi/Azure-APIM-Cross-Tenant-Signup-Bypass"}], "sourceIdentifier": "cve@mitre.org", "vulnStatus": "Awaiting Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-284"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "calver", "value": "[0,2025-10-17]"}}], "enrichment": {"confidence": 85.0, "confidence_source": "inferred", "scores": [{"score": 85.0, "source": "inferred"}]}, "product": "azure_api_management", "vendor": "microsoft"}], "created": "2026-07-24T04:30:04.070240+00:00", "title": "Cross\u2011Tenant Signup Bypass via Host Header Manipulation in Azure API Management", "updated": "2026-08-04T06:00:05.101223+00:00", "vendors": ["microsoft", "microsoft$PRODUCT$azure_api_management"]}