CVE-2025-53774: Microsoft 365 Copilot Information Vulnerability

CVE-2025-53774 Overview

CVE-2025-53774 is a high-severity information disclosure vulnerability affecting Microsoft 365 Copilot Chat (BizChat). This vulnerability allows unauthenticated attackers to exploit a command injection weakness (CWE-77) in the Microsoft 365 Copilot BizChat component, potentially leading to unauthorized disclosure of sensitive information. The network-based attack vector and low complexity make this vulnerability particularly concerning for organizations relying on Microsoft 365 Copilot for business communications and AI-assisted workflows.

Critical Impact

Unauthenticated attackers can potentially access confidential information processed by Microsoft 365 Copilot Chat through command injection, compromising data confidentiality across the organization.

Affected Products

• Microsoft 365 Copilot Chat

Discovery Timeline

• 2025-08-07 - CVE-2025-53774 published to NVD
• 2025-08-14 - Last updated in NVD database

Technical Details for CVE-2025-53774

Vulnerability Analysis

This vulnerability stems from improper neutralization of special elements used in a command (CWE-77) within the Microsoft 365 Copilot Chat component. The flaw enables attackers to inject malicious commands that are processed by the BizChat functionality, resulting in unauthorized information disclosure. Due to the nature of AI-assisted chat systems, the potential exposure includes conversation histories, organizational data, and sensitive business communications that Copilot processes on behalf of users.

The vulnerability can be exploited remotely without requiring authentication or user interaction, making it accessible to external threat actors. While the integrity and availability of the system remain unaffected, the confidentiality impact is significant, as attackers could potentially exfiltrate sensitive organizational data processed through the Copilot Chat interface.

Root Cause

The root cause of CVE-2025-53774 lies in insufficient input validation and command sanitization within the Microsoft 365 Copilot BizChat component. The system fails to properly neutralize user-supplied input before processing it as part of command execution, allowing specially crafted inputs to be interpreted as commands rather than data. This command injection flaw enables attackers to bypass intended security boundaries and access information that should be restricted.

Attack Vector

The attack vector is network-based, allowing remote exploitation without any privileges or user interaction. An attacker can craft malicious requests targeting the Microsoft 365 Copilot Chat service to inject commands that exploit the improper input handling. The low attack complexity indicates that the exploitation technique is straightforward once the vulnerability is understood.

The vulnerability affects the confidentiality of data processed by Copilot Chat, meaning successful exploitation could expose sensitive business communications, documents, and other organizational information that users interact with through the AI assistant.

Detection Methods for CVE-2025-53774

Indicators of Compromise

• Unusual or malformed requests to Microsoft 365 Copilot Chat endpoints containing command injection patterns
• Unexpected data access patterns or bulk information retrieval from Copilot Chat services
• Anomalous API calls to BizChat components from external or unauthorized sources
• Log entries showing command injection syntax in user input fields

Detection Strategies

• Monitor Microsoft 365 audit logs for suspicious Copilot Chat activity and unexpected data access patterns
• Implement network-level monitoring for unusual traffic patterns targeting Microsoft 365 Copilot endpoints
• Deploy security solutions capable of analyzing and alerting on command injection attempts in cloud service requests
• Review Microsoft Defender for Cloud Apps alerts related to anomalous Copilot usage

Monitoring Recommendations

• Enable comprehensive logging for Microsoft 365 Copilot Chat interactions and API calls
• Configure alerts for high-volume or unusual Copilot Chat queries from single sources
• Implement User and Entity Behavior Analytics (UEBA) to detect anomalous access patterns
• Regularly review Microsoft 365 security and compliance center for related alerts

How to Mitigate CVE-2025-53774

Immediate Actions Required

• Review the Microsoft Security Advisory for CVE-2025-53774 for official guidance
• Apply any available patches or updates from Microsoft for the 365 Copilot Chat service
• Implement network-level controls to restrict access to Copilot Chat from untrusted sources
• Enable conditional access policies to limit Copilot Chat usage to authenticated and compliant devices

Patch Information

Microsoft has addressed this vulnerability through their security update process. Organizations should consult the official Microsoft Security Response Center advisory for specific patch information and remediation guidance. As Microsoft 365 is a cloud-based service, patches are typically deployed automatically by Microsoft; however, administrators should verify their tenant is fully updated and review any configuration recommendations provided in the advisory.

Workarounds

• Restrict Microsoft 365 Copilot Chat access to trusted networks using conditional access policies until patches are confirmed
• Implement Data Loss Prevention (DLP) policies to monitor and protect sensitive information processed by Copilot
• Review and limit Copilot Chat permissions to minimize the scope of data accessible through the service
• Consider temporarily disabling Copilot Chat features for high-security environments until the vulnerability is fully remediated

Organizations should prioritize reviewing their Microsoft 365 security configurations and ensure all protective measures recommended by Microsoft are in place. Continuous monitoring of the Microsoft Security Response Center for updates regarding this vulnerability is strongly advised.