A zero-click data leak vulnerability has been uncovered in Microsoft 365 Copilot, an AI-powered assistant integrated into the Microsoft 365 productivity suite. This flaw allows an attacker to exfiltrate sensitive data without requiring any user interaction, such as clicking a link or opening a malicious file. The vulnerability likely stems from how Copilot processes or accesses user data to generate AI-driven insights and responses. Given the zero-click nature, exploitation could occur remotely and silently, potentially exposing confidential corporate or personal information handled within Microsoft 365 applications like Outlook, Word, Excel, or Teams. Although detailed technical specifics and affected versions are not disclosed, the high severity rating indicates significant risk. No patches or known exploits in the wild have been reported yet, but the presence of such a flaw in a widely used enterprise productivity platform raises concerns about data confidentiality and trust in AI integrations. The flaw was initially reported via Reddit's InfoSecNews community and covered by a reputable cybersecurity news outlet, BleepingComputer, underscoring its credibility and urgency.

For European organizations, this vulnerability poses a substantial threat to data confidentiality and privacy, especially given the strict regulatory environment under GDPR. Sensitive corporate data, intellectual property, and personal information processed through Microsoft 365 Copilot could be exposed without user awareness, leading to potential data breaches and compliance violations. The zero-click aspect increases the risk of widespread exploitation, as attackers do not need to rely on social engineering or user interaction, making detection and prevention more challenging. This could result in reputational damage, financial penalties, and operational disruptions. Additionally, organizations heavily reliant on Microsoft 365 for collaboration and communication may face increased risk of lateral movement by attackers if initial data leaks provide footholds within the network. The integration of AI tools into daily workflows amplifies the potential attack surface, making this vulnerability particularly impactful for enterprises embracing digital transformation.

Given the absence of official patches, European organizations should immediately review and tighten access controls and data governance policies around Microsoft 365 Copilot usage. Restricting Copilot's access to highly sensitive documents and limiting its deployment to essential users can reduce exposure. Employing robust monitoring and anomaly detection for unusual data access patterns within Microsoft 365 environments is critical to identify potential exploitation attempts early. Organizations should also enforce strict network segmentation and data loss prevention (DLP) solutions tailored to Microsoft 365 traffic. Engaging with Microsoft support to obtain guidance and updates on remediation timelines is advisable. Additionally, educating users and administrators about the risks of AI integrations and encouraging minimal data sharing with AI assistants until the vulnerability is resolved can help mitigate risk. Finally, organizations should prepare incident response plans specific to AI-related data leaks to ensure rapid containment and recovery.