vulnerability / NVI-00014003 / Revision 1
n8n: Per-Resource OAuth Consent Bypass via Unbound Refresh Token Resource Substitution
GitHub lists this reviewed advisory for n8n, n8n. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
n8n
source listed>= 2.38.0, < 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
n8n
source listed< 2.37.7
## 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
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-cw9w-vv67-hf73 ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.