Vulnerability-Lookup

GHSA-HH89-3R9W-QJ3J

Vulnerability from github – Published: 2026-09-10 15:11 – Updated: 2026-09-10 15:11

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.

Severity

8.7 (High)


                  
                    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

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "n8n"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.38.0"
            },
            {
              "fixed": "2.38.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "n8n"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.37.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-86075"
  ],
  "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"
  },
  "details": "## Impact\n\nThe 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.\n\n## Patches\n\nThe 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.\n\n## Workarounds\n\nIf upgrading is not immediately possible, administrators should consider the following temporary mitigations:\n- Restrict network access to the n8n instance so that only trusted clients can reach it.\n- Place the instance behind a reverse proxy configured to enforce strict request body size limits below the default 16 MiB.\n- Monitor database size for unexpected growth and audit the `oauth_clients` table for anomalous entries.\n\nThese workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.",
  "id": "GHSA-hh89-3r9w-qj3j",
  "modified": "2026-09-10T15:11:31Z",
  "published": "2026-09-10T15:11:31Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/n8n-io/n8n/security/advisories/GHSA-hh89-3r9w-qj3j"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-86075"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/n8n-io/n8n"
    },
    {
      "type": "WEB",
      "url": "https://github.com/n8n-io/n8n/releases/tag/n8n@2.37.7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/n8n-io/n8n/releases/tag/n8n@2.38.2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "n8n: Unauthenticated Persistent Storage Exhaustion via OAuth Dynamic Client Registration Endpoint"
}

CVE-2026-86075 (GCVE-0-2026-86075)

Vulnerability from cvelistv5 – Published: 2026-09-08 21:29 – Updated: 2026-09-09 16:03

Title

n8n: Unauthenticated Persistent Storage Exhaustion via OAuth Dynamic Client Registration Endpoint

Summary

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.

Severity

8.7 (High)


                        
                          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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-09 15:51 UTC

CWE

CWE-770 - Allocation of Resources Without Limits or Throttling

Assigner

GitHub_M mitre root

References

3 references

URL	Tags
https://github.com/n8n-io/n8n/security/advisories…	x_refsource_CONFIRM
https://github.com/n8n-io/n8n/releases/tag/n8n@2.37.7	x_refsource_MISC
https://github.com/n8n-io/n8n/releases/tag/n8n@2.38.2	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
n8n-io	n8n	Affected: < 2.37.7 Affected: >= 2.38.0, < 2.38.2

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JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-86075",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-09T15:51:52.294118Z",
                "version": "2.0.3"
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              "type": "ssvc"
            }
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        "providerMetadata": {
          "dateUpdated": "2026-09-09T16:03:52.236Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "n8n",
          "vendor": "n8n-io",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 2.37.7"
            },
            {
              "status": "affected",
              "version": "\u003e= 2.38.0, \u003c 2.38.2"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-770",
              "description": "CWE-770: Allocation of Resources Without Limits or Throttling",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-08T21:29:38.596Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/n8n-io/n8n/security/advisories/GHSA-hh89-3r9w-qj3j",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/n8n-io/n8n/security/advisories/GHSA-hh89-3r9w-qj3j"
        },
        {
          "name": "https://github.com/n8n-io/n8n/releases/tag/n8n@2.37.7",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/n8n-io/n8n/releases/tag/n8n@2.37.7"
        },
        {
          "name": "https://github.com/n8n-io/n8n/releases/tag/n8n@2.38.2",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/n8n-io/n8n/releases/tag/n8n@2.38.2"
        }
      ],
      "source": {
        "advisory": "GHSA-hh89-3r9w-qj3j",
        "discovery": "UNKNOWN"
      },
      "title": "n8n: Unauthenticated Persistent Storage Exhaustion via OAuth Dynamic Client Registration Endpoint"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-86075",
    "datePublished": "2026-09-08T21:29:38.596Z",
    "dateReserved": "2026-09-04T19:34:03.100Z",
    "dateUpdated": "2026-09-09T16:03:52.236Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.