CVE-2025-53787 is a command injection vulnerability classified under CWE-77 affecting Microsoft 365 Copilot's Business Chat feature. This vulnerability arises from improper neutralization of special elements used in commands, allowing attackers to inject and execute arbitrary commands remotely without authentication or user interaction. The vulnerability was published on August 7, 2025, with a CVSS v3.1 base score of 8.2, indicating high severity. The attack vector is network-based with low attack complexity and no privileges required, making exploitation feasible in many environments. The primary impact is on confidentiality, potentially allowing attackers to disclose sensitive information through unauthorized command execution. Integrity impact is limited, and availability is not affected. No patches have been published yet, and no known exploits are reported in the wild. The vulnerability affects all versions of Microsoft 365 Copilot Business Chat, though specific affected versions are not detailed. The flaw could be exploited by sending specially crafted input to the Business Chat interface, which fails to properly sanitize command elements, leading to injection. This vulnerability highlights the risks associated with integrating AI-driven chat features into enterprise productivity suites without robust input validation and command sanitization.

For European organizations, this vulnerability could lead to unauthorized disclosure of sensitive business information processed or accessible via Microsoft 365 Copilot's Business Chat. Given the widespread adoption of Microsoft 365 in Europe, especially among enterprises and government agencies, the potential impact is significant. Confidentiality breaches could expose intellectual property, personal data protected under GDPR, and strategic communications, leading to regulatory penalties and reputational damage. The lack of required authentication and user interaction lowers the barrier for attackers, increasing the risk of automated or large-scale exploitation attempts. Although availability and integrity impacts are limited, the confidentiality compromise alone can disrupt business operations and trust. Organizations in sectors such as finance, healthcare, and public administration are particularly vulnerable due to the sensitivity of their data and reliance on Microsoft 365 services. The absence of known exploits currently provides a window for proactive mitigation, but the high CVSS score underscores the urgency of addressing this vulnerability.

1. Monitor Microsoft security advisories closely and apply patches or updates for Microsoft 365 Copilot Business Chat immediately upon release. 2. Implement network segmentation and restrict access to Microsoft 365 services to trusted IP ranges to reduce exposure. 3. Employ Web Application Firewalls (WAFs) with custom rules to detect and block suspicious command injection patterns targeting Business Chat endpoints. 4. Enable detailed logging and continuous monitoring of Business Chat interactions to identify anomalous command execution attempts. 5. Conduct internal security assessments and penetration testing focusing on AI-driven chat interfaces to identify similar injection flaws. 6. Educate administrators and users about the risks of command injection and encourage reporting of unusual system behavior. 7. Consider disabling or limiting Business Chat features temporarily in high-risk environments until patches are available. 8. Integrate endpoint detection and response (EDR) solutions to detect lateral movement or data exfiltration attempts stemming from exploitation.