External risk intelligence

Microsoft Entra ID Remote Code Execution via Untrusted Data Deserialization

CVE advisoryKnown Exploit

CVE-2026-69836

Microsoft Entra ID is a cloud-based identity and access management service designed to be public-facing by default, serving as a primary gateway for authentication and identity services over the internet.

Deserialization

Microsoft Entra Id

Halo Surface Signal: 5 out of 5 — more likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A critical vulnerability has been identified in Microsoft Entra ID, a cloud-based identity and access management service. This issue, stemming from the deserialization of untrusted data, could allow unauthorized attackers to execute code remotely over a network, potentially impacting the integrity and availability of the service. The main concern is confirming relevance and exposure.

Untrusted data allows remote code execution.
Critical for cloud identity and access services.
Assess relevance and exposure of identity systems.

Attack Path

How an attacker could exploit the issue

An attacker could remotely send specially crafted data to Microsoft Entra ID, exploiting a deserialization flaw to execute arbitrary code. This could allow an unauthorized individual to take control of the system and access sensitive information.

Network exposure required.
Vulnerable to untrusted data deserialization.
Allows remote code execution.

Live Threat

Current exploitation, exposure, and threat context

A critical vulnerability in Microsoft Entra ID could allow an unauthenticated attacker to execute arbitrary code over a network. This could occur when the system deserializes untrusted data, potentially leading to a compromise of the service's integrity and confidentiality when supported by the advisory.

System code execution over network.
Untrusted data deserialization.
Service integrity and confidentiality compromised.

Operational Fix

Recommended remediation, mitigation, and detection steps

Real-World Ownership:

Given that Microsoft Entra ID is a cloud-based identity and access management service, the first practical move is to confirm its presence and accessibility within your environment. This likely involves collaboration between the platform team managing cloud services and the security team responsible for identity and access management. The immediate priority is to identify all instances of Microsoft Entra ID, assess their exposure, and determine business criticality to prioritize remediation efforts or implement compensating controls.

Ownership: Platform and Security teams.
Verify first: Entra ID presence and network exposure.
Action: Plan risk-based remediation.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

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Frequently asked questions

What is Microsoft Entra ID?

Microsoft Entra ID is a cloud-based identity and access management service. It functions as a central directory for organizations, managing user identities, controlling access to applications, and securing resources across cloud and on-premises environments.

What does deserialization of untrusted data mean for CVE-2026-69836?

This vulnerability, classified as CWE-502, occurs when the software takes data from an outside source and converts it back into an object without sufficient validation. An attacker can manipulate this process to inject malicious instructions, which the system then inadvertently runs as code.

How does an attacker trigger this vulnerability?

An attacker triggers this flaw by sending specially crafted data over a network to the Entra ID service. Simply interacting with the service through standard, legitimate user authentication processes does not trigger the bug; it requires the processing of malicious, malformed input designed to exploit the deserialization weakness.

Is my organization at risk from this CVE?

Because Microsoft Entra ID is a cloud-based identity service, Halo Surface Signal identifies it as public-facing by default. Organizations using this service should consider themselves relevant to this threat advisory, as the nature of the service requires internet connectivity to function as an authentication gateway.

What are the first steps to address this vulnerability?

Begin by coordinating between your platform and security teams to confirm the instances of Entra ID utilized in your environment. Once identified, evaluate the business criticality of these instances and collaborate on a risk-based remediation plan to apply official updates provided by the vendor.

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-69836

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.