CVE-2025-21187
📋 TL;DR
This vulnerability allows remote code execution in Microsoft Power Automate through improper control of generation of code (CWE-94). Attackers could execute arbitrary code on affected systems by crafting malicious inputs. Organizations using vulnerable versions of Power Automate are affected.
💻 Affected Systems
- Microsoft Power Automate
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the Power Automate server, allowing attackers to execute arbitrary commands, access sensitive data, and move laterally within the network.
Likely Case
Attackers gain initial foothold in the environment, potentially leading to data exfiltration, credential theft, or deployment of ransomware.
If Mitigated
Limited impact due to network segmentation, least privilege access, and monitoring controls preventing lateral movement.
🎯 Exploit Status
Exploitation requires understanding of Power Automate's code generation mechanisms and likely some level of access to the system.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft's monthly security updates for Power Automate
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21187
Restart Required: No
Instructions:
1. Review Microsoft's security advisory for CVE-2025-21187. 2. Apply the latest security updates for Power Automate through your update management system. 3. For cloud deployments, ensure you're on the latest service version. 4. Verify the update was successful.
🔧 Temporary Workarounds
Network Segmentation
allRestrict network access to Power Automate servers to only necessary users and systems
Principle of Least Privilege
allEnsure Power Automate service accounts have minimal necessary permissions
🧯 If You Can't Patch
- Implement strict network access controls to limit who can reach Power Automate servers
- Enable enhanced logging and monitoring for suspicious activities related to Power Automate
🔍 How to Verify
Check if Vulnerable:
Check your Power Automate version against Microsoft's security advisory for CVE-2025-21187Check Version:
For on-premises: Check Power Automate server version in control panel or via PowerShell. For cloud: Check version in Power Platform admin center.Verify Fix Applied:
Verify that your Power Automate version matches or exceeds the patched version specified in Microsoft's advisory📡 Detection & Monitoring
Log Indicators:
- Unusual process creation from Power Automate service
- Suspicious PowerShell or command execution events
- Failed authentication attempts to Power Automate
Network Indicators:
- Unexpected outbound connections from Power Automate servers
- Anomalous traffic patterns to/from Power Automate ports
SIEM Query:
source="PowerAutomate" AND (process_creation OR command_execution) AND severity=high