CVE-2026-86075: n8n: Unauthenticated Persistent Storage Exhaustion via OAuth Dynamic Client Registration Endpoint

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-08 · updated 2026-09-11
Weakness: CWE-770

Description

n8n is an open source workflow automation platform. Prior to 2.37.7 and 2.38.2, the OAuth Dynamic Client Registration endpoint bounded redirect_uris but accepted arbitrarily large client_name and grant_types values. An unauthenticated remote caller could repeatedly persist oversized values in oauth_clients and exhaust database storage. The affected validation is in packages/cli/src/modules/oauth-server/oauth-server.service.ts, including MAX_CLIENT_NAME_LENGTH and MAX_GRANT_TYPES. This issue is fixed in versions 2.37.7 and 2.38.2.

Affected products

n8n-io n8n: before 2.37.7; from 2.38.0 before 2.38.2 — fixed in 2.37.7, 2.38.2

How to fix

Upgrade to a fixed version: n8n-io n8n 2.37.7, 2.38.2. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-86075 or the next vulnerability affects your stack