OverDoS: Taking Down Over 70,000 n8n Instances
ID: f09a544e-9bc4-51da-b74e-89203bae00b2
STIX ID: report--f09a544e-9bc4-51da-b74e-89203bae00b2
Feed Name: Checkmarx Zero
Threat Score
The Checkmarx Zero team discovered a high-severity unauthenticated denial-of-service vulnerability (OverDoS, CVE-2026-42236, CVSS 8.7) and a moderate Open Redirect (CVE-2026-42230) in n8n that stem from an exposed, writable Dynamic Client Registration endpoint; OverDoS lets attackers persist large amounts of metadata to fill databases and render internet-facing instances non-responsive, with roughly 70,000 reachable instances identified—both issues were reported and patched in April 2026.
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