Entra ID | Breaking Cybersecurity News | The Hacker News

A critical token validation failure in Microsoft Entra ID (previously Azure Active Directory) could have allowed attackers to impersonate any user, including Global Administrators, across any tenant. The vulnerability, tracked as CVE-2025-55241 , has been assigned the maximum CVSS score of 10.0. It has been described by Microsoft as a privilege escalation flaw in Azure Entra. There is no indication that the issue was exploited in the wild. It has been addressed by the Windows maker as of July 17, 2025, requiring no customer action. Security researcher Dirk-jan Mollema, who discovered and reported the shortcoming on July 14, said the shortcoming made it possible to compromise every Entra ID tenant in the world, with the likely exception of national cloud deployments . The problem stems from a combination of two components: the use of service-to-service (S2S) actor tokens issued by the Access Control Service (ACS) and a fatal flaw in the legacy Azure AD Graph API (graph.windows.n...

If you invite guest users into your Entra ID tenant, you may be opening yourself up to a surprising risk.  A gap in access control in Microsoft Entra's subscription handling is allowing guest users to create and transfer subscriptions into the tenant they are invited into, while maintaining full ownership of them.  All the guest user needs are the permissions to create subscriptions in their home tenant, and an invitation as a guest user into an external tenant. Once inside, the guest user can create subscriptions in their home tenant, transfer them into the external tenant, and retain full ownership rights. This stealthy privilege escalation tactic allows a guest user to gain a privileged foothold in an environment where they should only have limited access. Many organizations treat guest accounts as low-risk based on their temporary, limited access, but this behavior, which works as designed, opens the door to known attack paths and lateral movement within the resource t...