CVE-2025-53787 is a high-severity command injection vulnerability (CWE-77) affecting Microsoft 365 Copilot's Business Chat feature. This vulnerability arises from improper neutralization of special elements used in operating system commands, allowing an unauthenticated remote attacker to execute arbitrary commands on the underlying system without requiring user interaction. The CVSS 3.1 base score of 8.2 reflects the critical impact on confidentiality (complete information disclosure), with limited impact on integrity and no impact on availability. The vulnerability is remotely exploitable over the network with low attack complexity and no privileges required, making it highly accessible to attackers. Although no known exploits are currently reported in the wild, the lack of available patches at the time of publication increases the urgency for mitigation. The vulnerability specifically targets Microsoft 365 Copilot's Business Chat, a component integrated into Microsoft 365 productivity suites that leverages AI-driven chat capabilities for business communications. Successful exploitation could lead to unauthorized disclosure of sensitive business information, potentially exposing confidential communications, intellectual property, or personal data. Given the integration of Microsoft 365 services in enterprise environments, this vulnerability poses a significant risk to organizations relying on these tools for daily operations.

For European organizations, the impact of this vulnerability is substantial due to the widespread adoption of Microsoft 365 services across various sectors including finance, healthcare, government, and manufacturing. The ability for an attacker to remotely execute commands and disclose sensitive information could lead to data breaches violating GDPR regulations, resulting in legal penalties and reputational damage. Confidential business communications and proprietary data could be exposed, undermining trust and competitive advantage. Additionally, the vulnerability could be leveraged as a foothold for further lateral movement within corporate networks, increasing the risk of broader compromise. The absence of required authentication and user interaction simplifies exploitation, raising the likelihood of targeted attacks against high-value European enterprises and public sector entities. This threat also aligns with the increasing targeting of cloud-based collaboration tools by cybercriminals and nation-state actors in Europe, amplifying its potential impact.

Given the absence of an official patch at the time of disclosure, European organizations should implement immediate compensating controls. These include restricting network access to Microsoft 365 Copilot Business Chat services via firewall rules and network segmentation to limit exposure. Employ robust monitoring and anomaly detection on network traffic and logs related to Microsoft 365 services to identify suspicious command execution attempts. Enforce strict data access policies and minimize the use of Business Chat features for highly sensitive communications until a patch is available. Organizations should also ensure that endpoint protection and intrusion detection systems are updated to detect potential exploitation patterns. Once Microsoft releases a security update, prioritize rapid deployment across all affected systems. Additionally, conduct security awareness training to inform users about the risks associated with this vulnerability and encourage reporting of unusual system behavior. Collaborate with Microsoft support channels for guidance and updates on remediation timelines.