n8n: Per-Resource OAuth Consent Bypass via Unbound Refresh Token Resource Substitution
cve-program · CVE-2026-86073
Publishedn8n 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.
Read the publisher's advisoryeuvd · EUVD-2026-73162
Publishedn8n 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.
Read the publisher's advisorynvd · CVE-2026-86073
Publishedn8n 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.
Read the publisher's advisoryosv · GHSA-cw9w-vv67-hf73
Published## 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.
Read the publisher's advisoryAffected versions, risk and source history
Exploitation and risk
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cve-program · CVE-2026-86073
Publishedn8n: Per-Resource OAuth Consent Bypass via Unbound Refresh Token Resource Substitution
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.
- Source published
- 8 Sep 2026 17:01:24 UTC
- Source modified
- 9 Sep 2026 15:58:40 UTC
- Saved here
- 23 Oct 2026 15:48:27 UTC
- Source terms
- CVE Program Terms of Use
Original source record · Cite this exact observation · Complete original publisher JSON
Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.
CVSS 4.0 · 5.9 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N
euvd · EUVD-2026-73162
Publishedn8n 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 …
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.
Additional publisher context
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
- Source published
- Sep 8, 2026, 5:01:24 PM (timezone not stated)
- Source modified
- Sep 9, 2026, 3:58:40 PM (timezone not stated)
- Saved here
- 13 Nov 2026 18:03:55 UTC
- Source terms
- ENISA EUVD · source terms and attribution apply
Original source record · Cite this exact observation · Complete original publisher JSON
Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.
EUVD CVSS 4.0 · 5.9 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N
nvd · CVE-2026-86073
Publishedn8n 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 …
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.
Additional publisher context
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.
- Source published
- 8 Sep 2026 17:18:39 UTC
- Source modified
- 11 Sep 2026 18:07:39 UTC
- Saved here
- 25 Oct 2026 16:19:16 UTC
- Source terms
- NIST NVD usage terms; underlying source attribution retained
Original source record · Cite this exact observation · Complete original publisher JSON
Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.
CVSS 4.0 · [email protected] · Secondary · 5.9 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 · [email protected] · Primary · 7.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:L
osv · GHSA-cw9w-vv67-hf73
Publishedn8n: Per-Resource OAuth Consent Bypass via Unbound Refresh Token Resource Substitution
## 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.
- Source published
- 10 Sep 2026 21:21:49 UTC
- Source modified
- 10 Sep 2026 21:30:04 UTC
- Saved here
- 24 Oct 2026 13:17:17 UTC
- Source terms
- GitHub Advisory Database · CC-BY-4.0
Original source record · Cite this exact observation · Complete original publisher JSON
Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.
CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N
Publisher rating · MODERATE