n8n: Unauthenticated Persistent Storage Exhaustion via OAuth Dynamic Client Registration Endpoint
cve-program · CVE-2026-86075
Publishedn8n 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.
Read the publisher's advisoryeuvd · EUVD-2026-74281
Publishedn8n 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.
Read the publisher's advisorynvd · CVE-2026-86075
Publishedn8n 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.
Read the publisher's advisoryosv · GHSA-hh89-3r9w-qj3j
Published## 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.
Read the publisher's advisoryAffected versions, risk and source history
Exploitation and risk
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cve-program · CVE-2026-86075
Publishedn8n: Unauthenticated Persistent Storage Exhaustion via OAuth Dynamic Client Registration Endpoint
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.
- Source published
- 8 Sep 2026 21:29:38 UTC
- Source modified
- 9 Sep 2026 16:03:52 UTC
- Saved here
- 23 Oct 2026 15:48:27 UTC
- Source terms
- CVE Program Terms of Use
Original source record · Cite this exact observation · Complete original publisher JSON
Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.
CVSS 4.0 · 8.7 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
euvd · EUVD-2026-74281
Publishedn8n 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 remot…
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.
Additional publisher context
EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.
Original publisher date fields
datePublished: Sep 8, 2026, 9:29:38 PM
dateUpdated: Sep 9, 2026, 4:03:52 PM
- Source published
- Sep 8, 2026, 9:29:38 PM (timezone not stated)
- Source modified
- Sep 9, 2026, 4:03:52 PM (timezone not stated)
- Saved here
- 13 Nov 2026 18:03:58 UTC
- Source terms
- ENISA EUVD · source terms and attribution apply
Original source record · Cite this exact observation · Complete original publisher JSON
Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.
EUVD CVSS 4.0 · 8.7 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
nvd · CVE-2026-86075
Publishedn8n 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 remot…
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.
Additional publisher context
NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.
Source analysis status: Analyzed
Weakness classifications: CWE-770
Original publisher date fields
published: 2026-09-08T22:19:16.250
lastModified: 2026-09-11T18:20:42.783
1 source CPE criteria · context only
- cpe:2.3:a:n8n:n8n:*:*:*:*:*:node.js:*:*
The original JSON retains the logical configuration operators, exclusions and version bounds.
- Source published
- 8 Sep 2026 22:19:16 UTC
- Source modified
- 11 Sep 2026 18:20:42 UTC
- Saved here
- 25 Oct 2026 16:19:16 UTC
- Source terms
- NIST NVD usage terms; underlying source attribution retained
Original source record · Cite this exact observation · Complete original publisher JSON
Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.
CVSS 4.0 · [email protected] · Secondary · 8.7 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 · [email protected] · Primary · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
osv · GHSA-hh89-3r9w-qj3j
Publishedn8n: Unauthenticated Persistent Storage Exhaustion via OAuth Dynamic Client Registration Endpoint
## 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.
- Source published
- 10 Sep 2026 15:11:31 UTC
- Source modified
- 10 Sep 2026 15:15:05 UTC
- Saved here
- 24 Oct 2026 13:17:17 UTC
- Source terms
- GitHub Advisory Database · CC-BY-4.0
Original source record · Cite this exact observation · Complete original publisher JSON
Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.
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
Publisher rating · HIGH