Microsoft patches flaw in Entra ID identity software

Microsoft warned on Aug. 20 that a maximum-severity deserialization flaw in Entra ID was actively exploited.

In releasing a patch for CVE-2026-69836, Microsoft said it had already fully mitigated the vulnerability, so there’s no further action for Entra ID users to take.

“The purpose of this CVE is to provide further transparency,” said Microsoft.

But many security pros weren't so sure.

“When Microsoft says no action is required, that applies to patching alone,” said Shane Barney, chief information security officer at Keeper Secuirty. “The flaw was confirmed exploited in the wild before Microsoft closed it, which means organizations still need to determine whether their environments were compromised during that window.”

Barney explained that CVE-2026-69836 let an unauthenticated attacker execute code over a network through a deserialization flaw in Microsoft Entra ID, the identity layer governing authentication across most enterprise Microsoft environments.

According to Barney, an attacker with that level of access to Entra ID can issue tokens, impersonate service principals and reach downstream resources using credentials that look entirely authorized. That access blends into normal traffic, which means there’s nothing to alert on unless teams are already watching, said Barney.

“Security teams should pull privileged access logs and authentication records from the exposure window and look for anomalous token issuance, unexpected service principal activity or access outside normal scope for affected accounts,” said Barney. “The patch closes the door on future exploitation but tells us nothing about what came through before it closed. Any security team that sees a confirmed exploitation notice should review access logs right now, not waiting for a second signal.”

Roman Sannikov, global research coordinator at iCounter, added that Microsoft’s “no action needed” statement is true for exactly one point: this specific flaw can't be exploited going forward because they fixed it on their end, not the customer’s end.

“That's not the same as saying you're in the clear,” said Sannikov. “Microsoft confirmed this was already being exploited in attacks before they patched it, and they still haven't said who was targeted, how long the exploitation window was open, or what attackers actually did once they had unauthenticated code execution against an identity provider sitting in front of Microsoft 365, Azure, and Dynamics CRM Online.”

Dmitry Sotnikov, chief product officer at Cayosoft, said teams can stop treating the underlying platform vulnerability as an active incident once Microsoft has confirmed it is resolved, but that does not necessarily mean there’s nothing left for the customer to validate.

Sotnikov said Microsoft secures the platform layer, while customers remain responsible for identities, permissions, privileged roles, security configuration, applications, and data access. If an attacker was able to take advantage of a platform vulnerability, Sotnikov said those are the areas where they may have escalated privileges, moved laterally, accessed data, or established persistence.

“No further action required should generally mean the provider does not require an additional remediation step,” said Sotnikov. “It should not automatically be interpreted as proof that nothing happened inside your tenant.”

Alex Wells, head of product strategy at Hadrian, added that Entra ID runs as a cloud service, so Microsoft has already fixed the vulnerability. Wells noted that Microsoft’s stance that the purpose of the CVE is to “provide further transparency” is exactly the kind of disclosure we want to see from vendors.

“However, saying that teams don’t need to take further action is only partially accurate,” said Wells. “There may be nothing left for customers to remediate, but Microsoft has confirmed that the vulnerability was exploited in the wild. Because Entra ID sits at the center of identity and access for many organizations, security teams should still investigate whether there are signs of compromise.”

Wells pointed out that Microsoft has disclosed very little about how the vulnerability was exploited, who was targeted, or what indicators defenders should look for. Wells said security teams should review Entra ID and related security logs for unusual activity involving privileged accounts, changes to roles or access policies, suspicious application or service-principal creation, and other unexpected identity activity.