CVE-2026-33103: Dynamics 365 Information Disclosure Flaw

CVE-2026-33103 Overview

CVE-2026-33103 is an improper access control vulnerability in Microsoft Dynamics 365 (on-premises) that allows an authorized attacker to disclose sensitive information locally. This vulnerability is classified under CWE-284 (Improper Access Control), indicating that the affected software fails to properly restrict access to critical resources or functionality.

Critical Impact

An authenticated local attacker can exploit insufficient access controls to gain unauthorized access to sensitive business data within Microsoft Dynamics 365 on-premises deployments, potentially exposing confidential customer information, financial records, or proprietary business intelligence.

Affected Products

• Microsoft Dynamics 365 (on-premises)

Discovery Timeline

• April 14, 2026 - CVE-2026-33103 published to NVD
• April 14, 2026 - Last updated in NVD database

Technical Details for CVE-2026-33103

Vulnerability Analysis

This vulnerability stems from improper access control mechanisms within Microsoft Dynamics 365 on-premises installations. The flaw enables an authorized user with local access to bypass intended security restrictions and access information beyond their privilege level. Given the local attack vector and requirement for low privileges, exploitation requires the attacker to already have some form of authenticated access to the target system.

The vulnerability specifically affects confidentiality, allowing unauthorized disclosure of sensitive data without impacting system integrity or availability. This makes it particularly concerning for organizations storing sensitive customer data, financial records, or proprietary business information within their Dynamics 365 deployments.

Root Cause

The root cause of CVE-2026-33103 is improper access control (CWE-284) within Microsoft Dynamics 365 on-premises. The vulnerability exists because the application fails to adequately enforce authorization checks when users attempt to access certain protected resources or data. This insufficient validation allows authenticated users to access information that should be restricted to higher-privileged accounts or different user contexts.

Attack Vector

The attack requires local access to the vulnerable system and low-level privileges. An attacker who has legitimate access to the Microsoft Dynamics 365 environment can exploit the improper access control mechanism to view or extract sensitive information they should not have access to. The attack does not require user interaction and can be executed with low complexity once the attacker has established local access.

Exploitation typically involves:

1. Gaining authenticated access to the Dynamics 365 on-premises environment
2. Identifying access control weaknesses in resource authorization
3. Leveraging the improper access control to query or access protected data
4. Extracting sensitive information beyond the attacker's authorized scope

Detection Methods for CVE-2026-33103

Indicators of Compromise

• Unusual data access patterns from user accounts accessing resources outside their normal scope
• Anomalous query patterns against Dynamics 365 databases or APIs
• Unexpected access to sensitive records or modules by lower-privileged users
• Audit log entries showing access attempts to restricted data entities

Detection Strategies

• Enable comprehensive auditing on Microsoft Dynamics 365 to capture all data access events
• Implement User and Entity Behavior Analytics (UEBA) to detect abnormal access patterns
• Configure alerting for access attempts to sensitive data entities by non-administrative users
• Review Dynamics 365 security roles and access logs for unauthorized privilege usage

Monitoring Recommendations

• Monitor Windows Security Event Logs for suspicious local authentication events
• Enable Dynamics 365 audit logging and regularly review access patterns
• Implement real-time alerting for bulk data access or export operations
• Use SentinelOne Singularity XDR to correlate endpoint activity with application-level access anomalies

How to Mitigate CVE-2026-33103

Immediate Actions Required

• Review and apply the latest security updates from Microsoft for Dynamics 365 on-premises
• Audit current user roles and permissions to enforce least-privilege access
• Enable comprehensive audit logging to track data access attempts
• Restrict local access to Dynamics 365 servers to authorized personnel only

Patch Information

Microsoft has released security guidance for this vulnerability. Administrators should consult the Microsoft CVE-2026-33103 Advisory for specific patch information and remediation steps. It is recommended to apply all available security updates for Microsoft Dynamics 365 on-premises deployments as soon as possible.

Workarounds

• Implement network segmentation to limit local access to Dynamics 365 servers
• Enable multi-factor authentication for all Dynamics 365 user accounts
• Apply strict role-based access control (RBAC) policies within Dynamics 365
• Monitor and restrict administrative and elevated access to essential personnel only

# Example: Enable Dynamics 365 audit logging via PowerShell
# Consult Microsoft documentation for your specific version
Set-CrmSetting -SettingType AuditSettings -Enabled $true
# Review security roles
Get-CrmSecurityRole | Export-Csv -Path "SecurityRolesAudit.csv"