n8n before 1.123.64, 2.x before 2.29.8, and before 2.30.1 contains a DOM-based cross-site scripting vulnerability in the HTML preview, which renders execution output into an iframe srcdoc without the sandbox attribute. A sanitizer bypass allows injected script to execute same-origin as the editor. When a victim opens the preview, the script can call authenticated APIs using the victim's session. An account with global:member privileges can exploit the issue.
https://www.vulncheck.com/advisories/n8n-before-dom-based-xss-via-unsandboxed-iframe
https://github.com/n8n-io/n8n/security/advisories/GHSA-p3rg-hrf9-w9gj
Published: 2026-07-22
Updated: 2026-07-22
Base Score: 4.3
Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:N
Severity: Medium
Base Score: 6.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Severity: Medium
Base Score: 8.2
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N
Severity: High
EPSS: 0.00534