CVE-2025-71389
CriticalCVSS 10.0Exploitation Probability (EPSS)
Elevated risk57th percentile - higher than 57% of all known CVEs
Summary
Cal.com (calcom/cal.diy) before version 5.9.9 is vulnerable to unauthenticated remote code execution. The application bundles a version of Next.js whose React Server Components (RSC) request handling deserializes attacker-controlled input. A remote attacker can send a crafted RSC request and cause arbitrary code execution on the server without authentication or user interaction. The flaw originates from CVE-2025-55182 in Next.js and is fixed in version 5.9.9 by updating the dependency.
Risk Assessment
An attacker can fully compromise the Cal.com server without any authentication, potentially leading to data theft, service disruption, or using the server for further attacks.
Recommendation
Immediately update Cal.com to version 5.9.9 or later, which includes the patched version of Next.js.
Other vulnerabilities in Cal.com
See all- CVE-2024-58354Critical
Vulnerability in the cal.com repository (later cal.diy) in GitHub Actions. The pr.yml workflow uses the pull_request_target trigger with default write permissions, allowing an attacker to execute arbitrary commands with the write-scoped GITHUB_TOKEN. An attacker can push commits, merge or mutate pull requests, add or delete comments, and delete or force-push branches.
- CVE-2024-58355High
Cal.com (calcom/cal.diy) through version 4.7.15 has a stored cross-site scripting (XSS) vulnerability in the single booking view (e.g., https://app.cal.com/booking/<id>). Booking-question field labels are rendered via React's dangerouslySetInnerHTML without sanitizing or escaping user input, allowing an attacker to inject arbitrary HTML/JavaScript.
- CVE-2024-58353High
XSS vulnerability in Cal.com (calcom/cal.diy) versions up to 4.7.15. Booking form field labels are rendered via React's dangerouslySetInnerHTML without proper sanitization, allowing injection of arbitrary HTML/JavaScript. Fixed in version 4.7.16.
- CVE-2023-37919Medium
Cal.com is scheduling software that has a vulnerability allowing active sessions to remain after enabling 2FA. When 2FA is activated on an account logged in on two or more devices, the other device(s) remain logged in without requiring identity verification.
Original NVD description (English source)
Cal.com (calcom/cal.diy) before 5.9.9 is vulnerable to unauthenticated remote code execution because it bundles a version of Next.js whose React Server Components (RSC) request handling deserializes attacker-controlled input. A remote attacker can send a crafted RSC request to the server and cause arbitrary code to be executed during server-side processing, without authentication or user interaction. The flaw derives from the upstream Next.js vulnerability CVE-2025-55182 and is resolved in 5.9.9 by updating the affected dependency.