CVE-2025-53774 is a medium-severity vulnerability classified under CWE-77, which pertains to improper neutralization of special elements used in a command, commonly known as command injection. This vulnerability affects Microsoft 365 Copilot's Business Chat feature, a component designed to facilitate business communications and workflows within the Microsoft 365 ecosystem. The flaw allows an attacker to inject malicious commands into the system due to insufficient sanitization or validation of user inputs before they are processed as commands. According to the CVSS 3.1 vector (6.5), the vulnerability can be exploited remotely (AV:N) without requiring any privileges (PR:N) or user interaction (UI:N), making it relatively easy to exploit. The impact primarily includes limited confidentiality and integrity loss, with no direct effect on availability. Although no known exploits are currently in the wild and no patches have been published yet, the vulnerability poses a risk of unauthorized information disclosure and potential manipulation of business chat data or commands within affected environments. Since the affected versions are not specified, it is presumed that the vulnerability could impact all or multiple deployments of Microsoft 365 Copilot's Business Chat until a patch is released.

For European organizations, this vulnerability could lead to unauthorized disclosure of sensitive business communications and data processed through Microsoft 365 Copilot's Business Chat. Given the widespread adoption of Microsoft 365 services across Europe, especially in sectors such as finance, healthcare, government, and manufacturing, exploitation could compromise confidential information, disrupt business processes, and erode trust in digital collaboration tools. The integrity impact means attackers might alter chat commands or data, potentially causing erroneous business decisions or workflow disruptions. Although availability is not directly affected, the indirect consequences of data manipulation or leakage could lead to regulatory scrutiny under GDPR and other data protection laws, resulting in financial penalties and reputational damage. The ease of exploitation without authentication increases the risk profile, especially for organizations with extensive remote or hybrid workforces relying on cloud-based collaboration tools.

To mitigate this vulnerability effectively, European organizations should: 1) Monitor official Microsoft security advisories closely and prioritize the deployment of patches or updates for Microsoft 365 Copilot's Business Chat as soon as they become available. 2) Implement strict input validation and sanitization controls at the application layer where possible, including the use of web application firewalls (WAFs) that can detect and block command injection patterns targeting business chat interfaces. 3) Restrict network access to Microsoft 365 services using conditional access policies and zero-trust principles, limiting exposure to only trusted users and devices. 4) Conduct regular security awareness training for employees to recognize suspicious activities or anomalies in business chat communications. 5) Employ advanced threat detection tools that can analyze chat traffic for unusual command patterns or data exfiltration attempts. 6) Review and tighten permissions and roles within Microsoft 365 to minimize potential damage from compromised accounts. 7) Prepare incident response plans specifically addressing cloud collaboration tool compromises to ensure rapid containment and remediation.