CVE-2026-54303: n8n: Reflected XSS via Facebook, WhatsApp, and Microsoft Teams Trigger Webhook Verification Endpoints

June 16, 2026 (updated July 20, 2026)

An endpoint in the Meta and Microsoft Teams trigger nodes reflects a query parameter into the HTTP response without sanitization or Content-Security-Policy headers, enabling reflected XSS in the n8n origin when a logged-in user visits a crafted URL.

References

github.com/advisories/GHSA-h86q-fx34-gfjr
github.com/n8n-io/n8n/security/advisories/GHSA-h86q-fx34-gfjr
nvd.nist.gov/vuln/detail/CVE-2026-54303

Code Behaviors & Features

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