n8n is an open source workflow automation platform. Prior to 2.37.7 and 2.38.1, the OAuth token endpoint bound an authorization code's first access token to the consented resource but did not bind its refresh token. Refreshing checked only that the requested resource was registered, not that it matched the original grant. An OAuth client approved for one workflow could substitute a different workflow URL in the resource parameter and obtain a valid token for an unapproved workflow accessible to the consenting user. This issue is fixed in versions 2.37.7 and 2.38.1.
n8n is an open source workflow automation platform. Prior to 2.37.7 and 2.38.1, the OAuth token endpoint bound an authorization code's first access token to the consented resource but did not bind its refresh token. Refreshing checked only that the requested resource was registered, not that it matched the original grant. An OAuth client approved for one workflow could substitute a different workflow URL in the resource parameter and obtain a valid token for an unapproved workflow accessible to the consenting user. This issue is fixed in versions 2.37.7 and 2.38.1.
n8n is an open source workflow automation platform. Prior to 2.37.7 and 2.38.1, the OAuth token endpoint bound an authorization code's first access token to the consented resource but did not bind its refresh token. Refreshing checked only that the requested resource was registered, not that it matched the original grant. An OAuth client approved for one workflow could substitute a different workflow URL in the resource parameter and obtain a valid token for an unapproved workflow accessible to the consenting user. This issue is fixed in versions 2.37.7 and 2.38.1.
## 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-term mitigation measures.
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, 5:01:24 PM
dateUpdated: Sep 9, 2026, 3:58:40 PM
No normalized affected-package data is projected for this source revision. The original publisher record may contain additional product and version evidence; this does not establish that a package is unaffected.
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-863
Original publisher date fields
published: 2026-09-08T17:18:39.167
lastModified: 2026-09-11T18:07:39.963
2 source CPE criteria · context only
cpe:2.3:a:n8n:n8n:*:*:*:*:*:node.js:*:*
cpe:2.3:a:n8n:n8n:2.38.0:*:*:*:*:node.js:*:*
The original JSON retains the logical configuration operators, exclusions and version bounds.
No normalized affected-package data is projected for this source revision. The original publisher record may contain additional product and version evidence; this does not establish that a package is unaffected.