critical
CVE-2026-21858
n8n Form Webhook Content-Type confusion allows unauthenticated arbitrary file read ("Ni8mare")
- Severity
- critical
- Affected product
- n8n
- Technology guide
- n8n security testing
- Affected versions
- n8n ≥ 1.65.0, < 1.121.0
- Fixed in
- n8n 1.121.0
- Detection basis
- Component version range
- Shipped rule
- n8n: n8n Form Webhook Content-Type confusion allows unauthenticated arbitrary file read ("Ni8mare")
- Added to NewScan
- 2026-08-10
- Detected by
- NewScan — free, self-hosted
How NewScan reports it
COMPONENT VERSION RANGE
NewScan fingerprints n8n from its response and reports this CVE when the detected version falls inside the affected range below.
References
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