🔴 Critical | Source: Microsoft Security Response Center
A vulnerability in Microsoft 365 Admin Center allows an attacker to gain elevated privileges over a network by exploiting improper verification of cryptographic signatures. Because Microsoft 365 Admin Center is used to manage users, licences, and security settings across an organisation’s Microsoft 365 tenancy, a successful exploit could give an attacker significant administrative control. This makes it a high-value target for threat actors seeking to compromise corporate environments.
Security Architect’s Take: Review and restrict network access to Microsoft 365 Admin Center using Conditional Access policies, enforcing phishing-resistant MFA and limiting admin portal access to trusted, managed devices and known IP ranges. Monitor for anomalous privilege changes in your audit logs and apply any available Microsoft patches or mitigations without delay.
Original advisory: CVE-2026-62873 Microsoft 365 Admin Center Elevation of Privilege Vulnerability