Cal.com vulnerabilities

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.

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.

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.

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.

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.