CVE-2026-33749 is a cross site scripting flaw in n8n, the workflow automation platform. NVD scores it 9.0 while the advisory rates it Moderate. An authenticated workflow editor can run script in a higher privileged user's session. Upgrade to 1.123.27, 2.13.3 or 2.14.1.
What's affected
n8n versions before 1.123.27, before 2.13.3, and before 2.14.1 are affected, depending on your release line. The patched versions are 1.123.27, 2.13.3 and 2.14.1.
The attacker needs permission to create or modify workflows. The advisory says a workflow could produce an HTML binary data object without a filename, and the /rest/binary-data endpoint served it inline on the n8n origin without Content-Disposition or Content-Security-Policy headers. The HTML then ran with full same origin script access. The attacker must also get the resulting URL to a higher privileged user.
How to check if you're exposed
n8n --version
npm ls n8n
For containers, check the image tag. Then review who has permission to create or edit workflows on your instance.
What to do now
- Upgrade to 1.123.27, 2.13.3 or 2.14.1, or later on your line.
- If you cannot upgrade, the advisory suggests limiting workflow creation and editing to fully trusted users, and restricting network access so untrusted users cannot reach binary data URLs. It says these do not fully remediate the risk.
- Be careful opening links to binary data from other users.
- If you suspect abuse, review workflow changes and rotate credentials stored in n8n.
Why it matters
The record uses CWE-79, cross site scripting. Serving user controlled HTML inline on the app's own origin lets it act as the logged in viewer. In n8n the viewer may be an admin, and the advisory names exfiltration of workflows and credentials, workflow changes and privilege escalation as outcomes. The record is not marked as exploited in the wild and is not in CISA KEV.
Browsers treat everything on one origin as one trust boundary. Serving user influenced HTML inline on the application's origin removes that boundary. Sending such files as downloads, with a content security policy that blocks scripts, keeps them from acting as the viewer. In n8n, also consider who needs the right to edit workflows, since that right is what the attack starts from.
Quick check
Does the attacker need an account?
Yes, with permission to create or modify workflows, per the advisory.
Sources
Last reviewed: 19 October 2026.
