Cal.com Broken Access Controls Exposes Millions of Bookings and Leads to Complete Account Takeover

Cybersecuritynews •Tushar Subhra Dutta • January 29, 2026

Cal.com, an open-source scheduling platform that millions of people use to book meetings and manage their calendars, recently faced a serious security problem. The platform provides an alternative to tools like Calendly, offering features like calendar syncing, team scheduling, and video conferencing. On January 26, 2026, security researchers discovered that attackers could break into any […]

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Cal.com Vulnerabilities Lead to Account Takeover and Data Exposure Cal.com, an open-source scheduling platform, experienced critical security vulnerabilities that allowed attackers to gain complete control over user accounts and access sensitive booking data. Discovered by security researchers on January 26, 2026, these flaws impacted millions of users, enabling unauthorized access to private meetings and organizational bookings. 2 sources 34

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Cal.com Broken Access Controls Exposes Millions of Bookings and Leads to Complete Account Takeover

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