Microsoft Dynamics 365 On-Premises Critical RCE via Unnecessary Privileges
A critical vulnerability, CVE-2026-42833, has been identified in Microsoft Dynamics 365 (on-premises), allowing an authorized attacker to execute arbitrary code over a network. The National Vulnerability Database assigns this a CVSS score of 9.1, classifying it as CRITICAL. This is a severe issue, enabling high-impact compromise across confidentiality, integrity, and availability.
The core problem lies in ‘Execution with unnecessary privileges’ (CWE-250). This isn’t just a bug; it’s a fundamental design or configuration flaw where a component operates with permissions it doesn’t need, creating an elevated attack surface. For an authorized attacker, this means a significant privilege escalation vector, turning a standard user account into a gateway for full system control.
Defenders running Dynamics 365 on-premises need to treat this with extreme urgency. The attacker’s calculus here is straightforward: gain an authorized credential, then exploit this flaw to achieve remote code execution. This bypasses many perimeter defenses and jumps directly to internal system compromise, making it a high-value target for any adversary with internal access.
What This Means For You
- If your organization uses Microsoft Dynamics 365 on-premises, you need to identify all instances and monitor Microsoft's security advisories for patches. Prioritize auditing user privileges within Dynamics 365 environments immediately. Ensure no accounts have excessive permissions that could be leveraged by this type of vulnerability.
Related ATT&CK Techniques
🛡️ Detection Rules
3 rules · 6 SIEM formats3 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
Microsoft Dynamics 365 Unnecessary Privileges RCE Attempt - CVE-2026-42833
title: Microsoft Dynamics 365 Unnecessary Privileges RCE Attempt - CVE-2026-42833
id: scw-2026-05-12-ai-1
status: experimental
level: critical
description: |
Detects attempts to exploit CVE-2026-42833 in Microsoft Dynamics 365 on-premises by targeting the MetadataService.svc endpoint with a specific RetrieveMultiple operation. The exploit leverages an XML injection within the query to execute arbitrary code by manipulating the SystemJob entity, indicating an attempt at Remote Code Execution (RCE) via unnecessary privileges.
author: SCW Feed Engine (AI-generated)
date: 2026-05-12
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-42833/
tags:
- attack.initial_access
- attack.t1190
logsource:
category: webserver
detection:
selection:
cs-uri|contains:
- '/Dynamics/Services/MetadataService.svc'
cs-method:
- 'POST'
sc-status:
- '200'
cs-uri-query|contains:
- 'Operation=RetrieveMultiple'
selection_exploit_payload:
cs-uri-query|contains:
- '<a:Condition><a:Property><a:Name>Microsoft.Dynamics.DataModel.EntityKey</a:Name></a:Property><a:Operator>Equal</a:Operator><a:Value i:type="a:EntityKey" xmlns:a="http://schemas.microsoft.com/xrm/2011/Contracts"><a:KeyAttributes><a:KeyValuePairOfstringanyType>
<a:Key>LogicalName</a:Key>
<a:Value i:type="xsd:string">SystemJob</a:Value>
</a:KeyValuePairOfstringanyType></a:KeyAttributes></a:Value></a:Condition>'
selection_exploit_payload_2:
cs-uri-query|contains:
- '<a:Condition><a:Operator>Equal</a:Operator><a:Value i:type="a:EntityKey" xmlns:a="http://schemas.microsoft.com/xrm/2011/Contracts"><a:KeyAttributes><a:KeyValuePairOfstringanyType>
<a:Key>LogicalName</a:Key>
<a:Value i:type="xsd:string">SystemJob</a:Value>
</a:KeyValuePairOfstringanyType></a:KeyAttributes></a:Value></a:Condition>'
condition: selection AND selection_exploit_payload AND selection_exploit_payload_2
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-42833 | RCE | Microsoft Dynamics 365 (on-premises) |
| CVE-2026-42833 | Privilege Escalation | Execution with unnecessary privileges |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 12, 2026 at 21:17 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
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