calendar invite scams

Calendar invite scams are a security threat that uses trusted collaboration tools to reach users. The tagged coverage focuses on a 2026 phishing campaign abusing Microsoft 365 Groups, Outlook calendar invitations, shared files, and OAuth authentication flows. Rather than relying only on spoofed email, attackers exploit familiar Microsoft 365 surfaces and cloud workflows, making suspicious activity harder to recognize and filter. This page collects reporting and discussion about how calendar invite scams affect corporate users and why organizations should treat unexpected invitations, shared content, and authentication requests with caution.