CVE-2026-57858
Stored XSS in Cal.com BookingPageTagManager allows authenticated event owners to inject JS.
Is CVE-2026-57858 being exploited?
Not confirmed. CVE-2026-57858 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.37% probability of exploitation in the next 30 days.
How severe is CVE-2026-57858?
CVE-2026-57858 is rated Critical. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-57858?
Not known from our data. No patch reference has been recorded for CVE-2026-57858, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2026-57858 affect?
CVE-2026-57858 affects Cal.com Cal.diy 2.1.1 - 6.2.0, Public booking pages using BookingPageTagManager. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-57858?
Apply vendor patch when released; meanwhile remove/validate analytics IDs, restrict event-owner inputs and add CSP.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated event owners can inject JavaScript into public booking pages to steal session cookies, forge authenticated requests, and wormably propagate via CSRF to other events.
Immediate action required
- affected>= 2.1.1 and <= 6.2.0
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.