CVE-2025-59286 is a command injection vulnerability classified under CWE-77, affecting Microsoft 365 Copilot's Business Chat. The flaw arises from improper neutralization of special elements in commands processed by the Business Chat feature, which could allow an attacker to inject and execute arbitrary commands remotely. The vulnerability is remotely exploitable over the network without requiring authentication but does require user interaction, such as clicking a malicious link or interacting with crafted input. The CVSS v3.1 base score is 6.5 (medium severity), reflecting high confidentiality impact but no impact on integrity or availability. The attack vector is network-based with low attack complexity and no privileges required. The vulnerability could enable attackers to exfiltrate sensitive data or perform unauthorized actions within the context of the Business Chat environment. No patches or known exploits are currently available, but the vulnerability is publicly disclosed and should be considered a significant risk for organizations relying on Microsoft 365 Copilot's Business Chat for business communications and workflows.

For European organizations, this vulnerability poses a risk primarily to confidentiality, potentially allowing attackers to extract sensitive business information communicated through Microsoft 365 Copilot's Business Chat. Given the widespread adoption of Microsoft 365 services across Europe, especially in sectors like finance, government, and healthcare, the exposure could lead to data breaches and loss of competitive advantage. Although the vulnerability does not impact system integrity or availability, the confidentiality breach could result in regulatory penalties under GDPR and damage to organizational reputation. The requirement for user interaction means phishing or social engineering campaigns could be leveraged to exploit this vulnerability, increasing the risk for organizations with less mature security awareness programs. The lack of a patch at the time of disclosure increases the window of exposure.

Until an official patch is released, European organizations should implement targeted mitigations beyond generic advice. These include: 1) Enhancing user awareness training focused on recognizing and avoiding phishing attempts and suspicious links related to Business Chat interactions; 2) Restricting access to Microsoft 365 Copilot's Business Chat to only essential users and enforcing strict access controls; 3) Monitoring network traffic and logs for unusual command patterns or anomalous Business Chat activity that could indicate exploitation attempts; 4) Employing application-layer firewalls or proxy solutions capable of detecting and blocking command injection payloads; 5) Coordinating with Microsoft support to obtain any available workarounds or mitigations; and 6) Reviewing and tightening data classification and sharing policies within Business Chat to limit sensitive data exposure. Organizations should prioritize patch deployment as soon as Microsoft releases an update addressing this vulnerability.