EUVD-2026-38754Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Low-privilege authenticated attacker stores payload affecting all form visitors (scope change); CSP limits confidentiality to non-cookie form data; no availability impact.
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
Lifecycle Timeline
3DescriptionCVE.org
n8n before 1.123.25 (1.x) and before 2.11.2 (2.x), with the fix also included in 2.12.0, contains a stored cross-site scripting vulnerability in the Form Trigger node's CSS sanitization that allows authenticated users to inject malicious scripts. Attackers with workflow creation permissions can inject XSS payloads that execute persistently for all form visitors, enabling form hijacking and phishing attacks.
AnalysisAI
Stored XSS in n8n's Form Trigger node allows any authenticated low-privilege user with workflow creation rights to inject persistent malicious scripts that execute for every visitor of a published form. Affects n8n 1.x before 1.123.25 and 2.x from 2.0.0-rc.0 before 2.11.2. No public exploit or active exploitation identified at time of analysis; the CVSS 4.0 score of 5.1 reflects partial CSP mitigation blocking session cookie theft while still permitting form hijacking and phishing against unlimited downstream victims.
Technical ContextAI
n8n is an open-source workflow automation platform distributed as the npm package 'n8n' (CPE: cpe:2.3:a:n8n:n8n). Its Form Trigger node allows users to publish externally accessible HTML forms that collect visitor-submitted data. The root cause is CWE-79 (Improper Neutralization of Input During Web Page Generation) specifically in the CSS sanitization logic applied to Form Trigger node inputs - the sanitizer fails to block injected JavaScript within CSS constructs, permitting stored payloads to persist in the published form's DOM. Unlike reflected XSS, the stored nature means a single injection event affects all subsequent form visitors without further attacker interaction. The vendor's existing Content Security Policy provides partial mitigation by preventing direct n8n session cookie exfiltration, but does not block script execution or manipulation of form submission targets.
RemediationAI
Vendor-released patches are available: upgrade n8n to version 2.11.2 or 2.12.0 (for 2.x deployments) or to 1.123.25 (for 1.x deployments), as confirmed by GHSA-q4fm-pjq6-m63g at https://github.com/n8n-io/n8n/security/advisories/GHSA-q4fm-pjq6-m63g. If immediate upgrade is not feasible, two vendor-documented temporary mitigations exist: first, restrict workflow creation and editing permissions to fully trusted users only, which reduces the attack surface to a smaller principal set but may disrupt operational workflows for broader teams; second, disable the Form Trigger node entirely by adding the string 'n8n-nodes-base.formTrigger' to the NODES_EXCLUDE environment variable, which eliminates the vulnerable attack surface entirely but renders all Form Trigger-based workflows non-operational until the patch is applied. The vendor explicitly notes these workarounds do not fully remediate the risk and should be treated as short-term measures only.
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Same weakness CWE-79 – Cross-site Scripting (XSS)
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External POC / Exploit Code
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