{ "dataType": "CVE_RECORD", "cveMetadata": { "state": "PUBLISHED", "cveId": "CVE-2025-66390", "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "assignerShortName": "mitre", "dateUpdated": "2026-07-22T15:47:05.047Z", "dateReserved": "2025-11-28T00:00:00.000Z", "datePublished": "2026-07-21T00:00:00.000Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "shortName": "mitre", "dateUpdated": "2026-07-21T13:27:24.472Z" }, "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)." } ], "tags": [ "disputed" ], "affected": [ { "vendor": "n/a", "product": "n/a", "versions": [ { "version": "n/a", "status": "affected" } ] } ], "references": [ { "url": "https://github.com/bountyyfi/Azure-APIM-Cross-Tenant-Signup-Bypass" }, { "url": "https://github.com/bountyyfi/Azure-APIM-Cross-Tenant-Signup-Bypass/security/advisories/GHSA-vcwf-73jp-r7mv" } ], "problemTypes": [ { "descriptions": [ { "type": "text", "lang": "en", "description": "n/a" } ] } ] }, "adp": [ { "problemTypes": [ { "descriptions": [ { "type": "CWE", "cweId": "CWE-284", "lang": "en", "description": "CWE-284 Improper Access Control" } ] } ], "references": [ { "url": "https://github.com/bountyyfi/Azure-APIM-Cross-Tenant-Signup-Bypass", "tags": [ "exploit" ] } ], "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", "baseScore": 9.8, "attackVector": "NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH" } }, { "other": { "type": "ssvc", "content": { "timestamp": "2026-07-22T15:18:22.488125Z", "id": "CVE-2025-66390", "options": [ { "Exploitation": "poc" }, { "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": "2026-07-22T15:47:05.047Z" } } ] }, "dataVersion": "5.2" }