n8n is a workflow automation platform. From 1.77.0 to before 1.98.2, a stored Cross-Site Scripting (XSS) vulnerability was identified in n8n, specifically in the Form Trigger node's HTML form element. An authenticated attacker can inject malicious HTML via an <iframe> with a srcdoc payload that includes arbitrary JavaScript execution.

The attacker can also inject malicious Javascript by using <video> coupled <source> using an onerror event. While using iframe or a combination of video and source tag, this vulnerability allows for Account Takeover (ATO) by exfiltrating n8n-browserId and session cookies from authenticated users who visit a maliciously crafted form. Using these tokens and cookies, an attacker can impersonate the victim and change account details such as email addresses, enabling full control over the account-especially if 2FA is not enabled.

Users should upgrade to version >= 1.98.2.