Authorization Flaw in n8n (CVE-2026-86073)
Summary
Vulnerability in n8n (CVE-2026-86073). Confidential information can be exposed externally. Mitigation: upgrade to 2.37.7 or later.
Original description
The description as published by the source.
Impact
The OAuth token endpoint bound an authorization code's first access token to the consented resource, but not its refresh token. Refreshing only checked that the requested resource was registered, not that it matched the original grant. An OAuth client approved for one workflow could refresh with a different workflow's URL and get a valid, unapproved token for it. The patch binds refresh tokens to the granted resource and rejects mismatches.
Exploitation requires the attacker to register an OAuth client, convince an authenticated user to approve that client for one known protected resource, and know the URL of a second protected resource that the consenting user is permitted to execute.
Patches
The issue has been fixed in n8n versions 2.38.1 and 2.37.7. Users should upgrade to this version 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.
- Deactivate MCP Trigger, form, and webhook workflows that are protected by the n8n OAuth server if they are not required.
- Audit connected OAuth clients and revoke any that are not recognized or no longer needed.
- Require re-authorization for all existing OAuth clients after upgrading, as previously issued refresh tokens did not store the original resource binding.
These workarounds do not fully remediate the risk and should only be used as short-…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-86073 has been found in n8n.
Confidential information can be exposed externally. CVSS score: 7.6/10.
What to do: upgrade n8n to 2.37.7 or later.
If unsure, ask your IT team or search "n8n CVE-2026-86073" on the vendor's site.
CVE-2026-86073 (n8n) — CWE-863 / CVSS v3 7.6
Attack vector: remote (network-reachable) / unauthenticated
Patched: 2.37.7 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Incorrect authorization (CWE-863) exists in n8n.
Check the vendor advisory for the affected versions of n8n.
Severity: High (CVSS 7.6/10). Confidential information can be exposed externally.
Update to 2.37.7.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'n8n' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'n8n' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
n8nを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade n8n to 2.37.7ステージング環境で 2.37.7 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- web github.com
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- web nvd.nist.gov
- web github.com