CVE-2026-57858 Cal.com Cal.diy 6.2.0 Stored XSS via BookingPageTagManager Analytics Tracking ID
Authenticated users can inject JavaScript into booking pages via analytics IDs, stealing visitor sessions and enabling wormable propagation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-57858?
CVE-2026-57858 is a critical cross-site scripting vulnerability in Cal.com Self-Hosted (Cal.diy), published on 12 Aug 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-79
Which versions are affected by CVE-2026-57858?
How do I fix CVE-2026-57858?
No fix has been published for CVE-2026-57858 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-57858 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-57858 exists.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-5m2w-xrqj-9hhh.