CVE-2025-53774
📋 TL;DR
This vulnerability in Microsoft 365 Copilot BizChat allows authenticated attackers to access sensitive information from other users' business chats. It affects organizations using Microsoft 365 Copilot with BizChat functionality. The vulnerability stems from improper neutralization of special elements used in a command.
💻 Affected Systems
- Microsoft 365 Copilot
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could access confidential business discussions, intellectual property, financial data, or personally identifiable information from other users' Copilot BizChat sessions, leading to data breaches and regulatory violations.
Likely Case
Internal users with legitimate access could inadvertently or intentionally view other users' business chat data, potentially exposing sensitive project discussions or confidential communications.
If Mitigated
With proper access controls and monitoring, impact is limited to minimal data exposure that can be quickly detected and contained.
🎯 Exploit Status
Exploitation requires authenticated access to Microsoft 365 Copilot and knowledge of the specific vulnerability in BizChat functionality.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Security update released in May 2025
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53774
Restart Required: No
Instructions:
1. Apply the latest Microsoft 365 Copilot security updates via Microsoft Update or Microsoft 365 admin center. 2. Ensure all Copilot instances are updated to the patched version. 3. Verify update completion through Microsoft 365 admin portal.
🔧 Temporary Workarounds
Restrict Copilot Access
allTemporarily limit Microsoft 365 Copilot access to essential personnel only while awaiting patch deployment.
Monitor BizChat Activity
allIncrease monitoring of Copilot BizChat usage patterns and access logs for unusual activity.
🧯 If You Can't Patch
- Implement strict access controls and least privilege principles for Microsoft 365 Copilot users
- Enable enhanced auditing and monitoring for all Copilot BizChat activities
🔍 How to Verify
Check if Vulnerable:
Check Microsoft 365 Copilot version in Microsoft 365 admin center and compare against patched versions listed in Microsoft Security Advisory.Check Version:
Check version through Microsoft 365 admin center or PowerShell: Get-OrganizationConfig | Select-Object *Copilot*Verify Fix Applied:
Verify that Microsoft 365 Copilot has received the May 2025 security updates and confirm version is updated in admin portal.📡 Detection & Monitoring
Log Indicators:
- Unusual patterns of Copilot BizChat access
- Multiple user accounts accessing same BizChat sessions
- Access attempts to BizChat data outside normal patterns
Network Indicators:
- Unusual API calls to Copilot BizChat endpoints
- Abnormal data transfer volumes from Copilot services
SIEM Query:
source="Microsoft 365" AND (event="CopilotAccess" OR event="BizChatAccess") AND user!=target_user | stats count by user, target_user, timestamp