Vulnerability-Lookup

GHSA-Q5XF-XHWF-CWQF

Vulnerability from github – Published: 2026-07-22 22:31 – Updated: 2026-07-22 22:31

Summary

n8n: Member-Level Users Can Execute Other Users' MCP Server Trigger Workflows via Missing OAuth Authorization Check

Details

Impact

The OAuth 2.1 consent and token-issuance flow introduced in n8n 2.27.0 does not verify that the authenticated user has access to the workflow referenced as the OAuth resource. A member-level user can register an OAuth client, self-approve consent for another user's n8n OAuth2-protected MCP Server Trigger workflow, and obtain a valid token for it.

The workflow runs in the owner's project context with the owner's stored credentials. The attacker sets the tool inputs and reads the outputs, which may include data from the owner's connected integrations, breaking user and project isolation. The resulting executions appear under the owner's account and are not visible to the attacker.

This issue only affects instances running n8n 2.27.0 or later where at least one active workflow uses an MCP Server Trigger node configured with n8n OAuth2 authentication.

Patches

The issue has been fixed in n8n versions 2.29.8 and 2.30.1. 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 n8n instance access to fully trusted users only. - Audit active workflows using the MCP Server Trigger with n8n OAuth2 authentication and consider switching to a different authentication method or deactivating them until the patch is applied.

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

Severity

5.1 (Medium)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:L/SA:N

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JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "n8n"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.30.0"
            },
            {
              "fixed": "2.30.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "n8n"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.29.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-65594"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-863"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-22T22:31:01Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Impact\nThe OAuth 2.1 consent and token-issuance flow introduced in n8n 2.27.0 does not verify that the authenticated user has access to the workflow referenced as the OAuth resource. A member-level user can register an OAuth client, self-approve consent for another user\u0027s `n8n OAuth2`-protected MCP Server Trigger workflow, and obtain a valid token for it.\n\nThe workflow runs in the owner\u0027s project context with the owner\u0027s stored credentials. The attacker sets the tool inputs and reads the outputs, which may include data from the owner\u0027s connected integrations, breaking user and project isolation. The resulting executions appear under the owner\u0027s account and are not visible to the attacker.\n\nThis issue only affects instances running n8n 2.27.0 or later where at least one active workflow uses an MCP Server Trigger node configured with `n8n OAuth2` authentication.\n\n## Patches\nThe issue has been fixed in n8n versions 2.29.8 and 2.30.1. Users should upgrade to one of these versions or later to remediate the vulnerability.\n\n## Workarounds\nIf upgrading is not immediately possible, administrators should consider the following temporary mitigations:\n- Restrict n8n instance access to fully trusted users only.\n- Audit active workflows using the MCP Server Trigger with `n8n OAuth2` authentication and consider switching to a different authentication method or deactivating them until the patch is applied.\n\nThese workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.",
  "id": "GHSA-q5xf-xhwf-cwqf",
  "modified": "2026-07-22T22:31:01Z",
  "published": "2026-07-22T22:31:01Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/n8n-io/n8n/security/advisories/GHSA-q5xf-xhwf-cwqf"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-65594"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/n8n-io/n8n"
    },
    {
      "type": "WEB",
      "url": "https://github.com/n8n-io/n8n/releases/tag/n8n@2.29.8"
    },
    {
      "type": "WEB",
      "url": "https://github.com/n8n-io/n8n/releases/tag/n8n@2.30.1"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/n8n-before-missing-oauth-authorization-check"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "n8n: Member-Level Users Can Execute Other Users\u0027 MCP Server Trigger Workflows via Missing OAuth Authorization Check"
}

CVE-2026-65594 (GCVE-0-2026-65594)

Vulnerability from cvelistv5 – Published: 2026-07-22 11:21 – Updated: 2026-10-29 21:16

Title

n8n before 2.30.1 Missing OAuth Authorization Check

Summary

n8n before 2.29.8 and 2.30.x before 2.30.1 (affected from 2.27.0, when the OAuth 2.1 consent and token-issuance flow was introduced) does not verify that the authenticated user has access to the workflow referenced as the OAuth resource. On instances with at least one active MCP Server Trigger workflow configured with n8n OAuth2 authentication, a member-level user can register an OAuth client, self-approve consent for another user's workflow, and obtain a valid token. The workflow then runs in the owner's project context with the owner's stored credentials, and the attacker can set tool inputs and read outputs (potentially including data from the owner's connected integrations), breaking user and project isolation.

Severity

5.1 (Medium)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:H/SI:L/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-23 18:01 UTC

CWE

CWE-863 - Incorrect Authorization

Assigner

VulnCheck CNA under the mitre root

CNA scorecard B 84/100 over 7818 records in the last 180 days details

References

2 references

URL	Tags
https://github.com/n8n-io/n8n/security/advisories…	vendor-advisory
https://www.vulncheck.com/advisories/n8n-before-m…	third-party-advisory

Impacted products

2 products

Vendor	Product	Version
n8n-io	n8n	Affected: 2.30.0 , < 2.30.1 (semver) Unaffected: 2.30.1 (semver)
n8n-io	n8n	Affected: 0 , < 2.29.8 (semver) Unaffected: 2.29.8 (semver)

Date Public

2026-07-08 00:00

Show details on NVD website

JSON

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                "id": "CVE-2026-65594",
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                  },
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                "role": "CISA Coordinator",
                "timestamp": "2026-07-23T18:01:20.810448Z",
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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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

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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.
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