CVE-2025-66390 (GCVE-0-2025-66390)

Vulnerability from cvelistv5 – Published: 2026-07-21 00:00 – Updated: 2026-07-22 15:47 Disputed
VLAI
Summary
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).
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: poc Automatable: yes Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-22 15:18 UTC
CWE
  • n/a
  • CWE-284 - Improper Access Control
Assigner
mitre CNA under the mitre root
CNA scorecard E 29/100 over 2146 records in the last 180 days details
References
Show details on NVD website
To clipboard 

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