CVE-2025-53774 is a command injection vulnerability classified under CWE-77 affecting Microsoft 365 Copilot's Business Chat feature. This vulnerability stems from improper neutralization of special elements used in commands, which allows an attacker to inject and execute arbitrary commands remotely. The flaw does not require any authentication or user interaction, making it accessible over the network with low attack complexity. The vulnerability impacts the confidentiality and integrity of data processed or accessible through the Business Chat feature, potentially enabling unauthorized data disclosure or manipulation. The CVSS v3.1 base score is 6.5, reflecting a medium severity level, with attack vector network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction (UI:N). The scope remains unchanged (S:U), indicating the vulnerability affects only the vulnerable component. Although no known exploits have been reported in the wild and no patches have been published yet, the vulnerability poses a significant risk due to the widespread use of Microsoft 365 Copilot in enterprise environments. The lack of patches necessitates immediate attention to mitigation strategies to prevent exploitation. The vulnerability's presence in a productivity tool integrated deeply into business workflows increases the risk of sensitive information leakage or unauthorized command execution, which could disrupt business operations or compromise data integrity.

For European organizations, this vulnerability could lead to unauthorized disclosure of sensitive business information and manipulation of data within Microsoft 365 Copilot's Business Chat environment. Given the integration of Copilot into daily business communications and workflows, exploitation could compromise confidential corporate data, intellectual property, or customer information. The integrity of business communications could be undermined, potentially leading to misinformation or fraudulent activities. Although availability is not directly impacted, the loss of confidentiality and integrity could have severe reputational and regulatory consequences, especially under GDPR and other data protection laws. Organizations relying heavily on Microsoft 365 Copilot for business chat and collaboration are at heightened risk. The vulnerability's remote exploitability without authentication increases the threat landscape, potentially allowing attackers to target multiple organizations at scale. This could be particularly damaging for sectors like finance, legal, healthcare, and government entities across Europe, where data sensitivity and compliance requirements are stringent.

Until an official patch is released, European organizations should implement several specific mitigation measures. First, restrict network access to Microsoft 365 Copilot Business Chat features by using conditional access policies and network segmentation to limit exposure. Implement strict input validation and sanitization controls on any user inputs that interact with the Business Chat feature, if customization or integration points exist. Monitor logs and alerts for unusual command execution patterns or anomalous behavior within Microsoft 365 environments. Employ Microsoft Defender for Office 365 and other advanced threat protection tools to detect and block suspicious activities. Educate users and administrators about the risk and encourage vigilance against unexpected behaviors in the Business Chat feature. Coordinate with Microsoft support and subscribe to security advisories to receive timely updates and patches. Consider temporarily disabling the Business Chat feature in sensitive environments if feasible until a fix is available. Finally, review and reinforce incident response plans to quickly address potential exploitation attempts.