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CVE-2026-57858

Status: DeferredCritical (9.3)—

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.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

XSS almacenado en componente público (CWE-79) ejecuta JavaScript en navegadores de visitantes sin sanitización. Requiere autenticación pero propaga sin interacción adicional del usuario final, encajando en T1189. Impactos: ejecución de código JavaScript (T1059.007), robo de cookies de sesión (T1539)

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Restrict Web-Based ContentUser TrainingUpdate SoftwareMulti-factor AuthenticationExecution PreventionBehavior Prevention on Endpoint

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

CAL — Cal.diyAI

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2026-57858",
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          "options": [
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              "automatable": "no"
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          "version": "2.0.3",
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    "cvssMetricV40": [
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          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
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        {
          "vendor": "Cal.com",
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    {
      "url": "https://github.com/calcom/cal.com",
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    {
      "url": "https://www.vulncheck.com/advisories/cal-com-cal-diy-stored-xss-via-bookingpagetagmanager-analytics-tracking-id",
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    }
  ],
  "lastModified": "2026-09-24T20:06:30.133",
  "sourceIdentifier": "disclosure@vulncheck.com"
}