CVE-2026-21858 — n8n
CRITICALCVE-2026-21858 is a critical-severity (CVSS 10) Improper Input Validation vulnerability in n8n. 3 public exploit or proof-of-concept references are indexed, so weaponization risk is real. A fix is available for n8n — see the affected versions and patch details below.
n8n Vulnerable to Unauthenticated File Access via Improper Webhook Request Handling
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- 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-2026-21858.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
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
A vulnerability in n8n allows an attacker to access files on the underlying server through execution of certain form-based workflows. A vulnerable workflow could grant access to an unauthenticated remote attacker. This could result in exposure of sensitive information stored on the system and may enable further compromise depending on deployment configuration and workflow usage.
Patches
The issue has been fixed in n8n version 1.121.0. Users should upgrade to this version or later to remediate the vulnerability.
Workarounds
No official workarounds are available. As a temporary mitigation, users may restrict or disable publicly accessible webhook and form endpoints until upgrading.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | n8n | ≥ 1.65.0&&< 1.121.0 | 1.121.0npm install n8n@1.121.0 |
Affected Products
n8nn8nResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Chocapikk/CVE-2026-21858
n8n Ni8mare - Unauthenticated Arbitrary File Read to RCE Chain (CVSS 10.
ZeroDayEvil/CVE-2026-21858-n8n-FullChain
🛡️ Official AI Security Tool module for CVE-2026-21858 + CVE-2025-68613
sh4den/CVE-2026-21858
Proof of Concept: CVE-2026-21858 is vulnerability on n8n where unauthent
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 1.121.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-21858 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 to detect CVE-2026-21858
A community-maintained Nuclei template exists for this CVE. You can scan for it directly:
nuclei -id cve-2026-21858 -u https://target- Template
- n8n Webhooks - Remote Code Execution
- Severity
- critical
- Impact
- Unauthenticated remote attackers can access sensitive files, potentially leading to information disclosure and further system compromise.
- Remediation
- Update to version 1.121.0 or later.
Template by ProjectDiscovery nuclei-templates (rxerium), MIT licensed. View the full template. Scan only systems you are authorised to test.
Frequently Asked Questions
Is CVE-2026-21858 in your dependencies?
Find it across npm, including transitive dependencies.