CVE-2026-57858: Cal.com Self-Hosted Cal.diy

High severity, CVSS 8.9. EPSS: 0.4% chance of exploitation in the next 30 days.

Cal.com Cal.diy versions 2.1.1 through 6.2.0 contain a stored cross-site scripting vulnerability in the BookingPageTagManager component that allows authenticated event owners to inject arbitrary JavaScript by supplying a malicious analytics tracking ID without sanitization. Attackers can close the inline script string literal with a crafted payload that executes in the browser of every visitor to the affected public booking page, enabling session cookie theft, forged authenticated requests, and wormable propagation by chaining with CSRF-able endpoints to persist payloads on additional events.

Affected products

• Cal.com Cal.com Self-Hosted Cal.diy: from 2.1.1, up to and including 6.2.0

Published 2026-08-12. Last modified 2026-09-24.