GHSA-hh89-3r9w-qj3j

Suggest an improvement
Source
https://github.com/advisories/GHSA-hh89-3r9w-qj3j
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-hh89-3r9w-qj3j/GHSA-hh89-3r9w-qj3j.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-hh89-3r9w-qj3j
Aliases
Downstream
Published
2026-09-10T15:11:31Z
Modified
2026-09-10T15:15:05Z
Severity
  • 8.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N CVSS Calculator
Summary
n8n: Unauthenticated Persistent Storage Exhaustion via OAuth Dynamic Client Registration Endpoint
Details

Impact

The OAuth Dynamic Client Registration endpoints validated field sizes only for redirect_uris, leaving client_name and grant_types bounded by presence checks alone. An unauthenticated remote caller could submit arbitrarily large values in either field and have them persisted to the database. Repeated registration therefore grew persistent storage without limit and without any account on the instance. The patch caps client_name at its column length and limits grant_types to the grant types the server actually implements, with the array capped at that count.

Patches

The issue has been fixed in n8n versions 2.37.7 and 2.38.2. 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:

  • Restrict network access to the n8n instance so that only trusted clients can reach it.
  • Place the instance behind a reverse proxy configured to enforce strict request body size limits below the default 16 MiB.
  • Monitor database size for unexpected growth and audit the oauth_clients table for anomalous entries.

These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.

Database specific 
{
    "cwe_ids":  [
        "CWE-770"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-09-10T15:11:31Z",
    "nvd_published_at":  "2026-09-08T22:19:16Z",
    "severity":  "HIGH"
}
References

Affected packages

npm / n8n

Package

Name
n8n
View open source insights on deps.dev
Purl
pkg:npm/n8n

Affected ranges

Type
SEMVER
Events
Introduced
2.38.0
Fixed
2.38.2

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-hh89-3r9w-qj3j/GHSA-hh89-3r9w-qj3j.json"

npm / n8n

Package

Name
n8n
View open source insights on deps.dev
Purl
pkg:npm/n8n

Affected ranges

Type
SEMVER
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Fixed
2.37.7

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/09/GHSA-hh89-3r9w-qj3j/GHSA-hh89-3r9w-qj3j.json"