CVE-2026-77072: n8n before 1.123.69 Stored XSS via Form Completion Page

Severity: high (CVSS 7.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-20 · updated 2026-09-01
Weakness: CWE-79

Description

n8n before 1.123.69, 2.33.4, and 2.34.1 contains a stored cross-site scripting vulnerability in the Form node's completion page. The completion page applied its sandboxing Content-Security-Policy only when respondWith was not set to 'redirect', but responseText was always rendered as raw HTML. An authenticated member could set respondWith to 'redirect' via an expression while keeping responseText populated, causing the completion page to serve unsanitized HTML and script from the n8n origin. Any visitor who submitted the resulting public form would have that script execute same-origin with their session.

Affected products

n8n-io n8n: before 1.123.69; from 2.33.0 before 2.33.4; 2.34.0 — fixed in 1.123.69, 2.33.4

How to fix

Upgrade to a fixed version: n8n-io n8n 1.123.69, 2.33.4. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-77072 or the next vulnerability affects your stack