CVE-2026-56356 — n8n
CVE-2026-56356 is a security vulnerability in n8n. A fix is available for n8n — see the affected versions and patch details below.
n8n - Stored Cross-Site Scripting in Chat Trigger Node Custom CSS Field
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-56356.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
n8nnpmDescription
Impact
An authenticated user with permission to create or modify workflows could inject malicious JavaScript into the Custom CSS field of the Chat Trigger node. Due to a misconfiguration in the sanitize-html library, the sanitization could be bypassed, resulting in stored XSS on the public chat page. Any user visiting the chat URL would be affected.
Patches
The issue has been fixed in n8n versions 1.123.27, 2.13.3, and 2.14.1. Users should upgrade to one of these versions or later to remediate the vulnerability.
Workarounds
If upgrading is not immediately possible, administrators should consider the following temporary mitigations:
- Limit workflow creation and editing permissions to fully trusted users only.
- Disable the Chat Trigger node by adding
@n8n/n8n-nodes-langchain.chatTriggerto theNODES_EXCLUDEenvironment variable.
These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | n8n | all versions | 1.123.27npm install n8n@1.123.27 |
| 📦npm | n8n | ≥ 2.14.0&&< 2.14.1 | 2.14.1npm install n8n@2.14.1 |
| 📦npm | n8n | ≥ 2.0.0-rc.0&&< 2.13.3 | 2.13.3npm install n8n@2.13.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for n8n, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update n8n to 1.123.27 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-56356 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-56356 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-56356. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-56356 in your dependencies?
O3 Security finds CVE-2026-56356 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.