Medium

n8n has Open Redirect in MCP OAuth Consent Flow

  • Disclosed: 29.04.2026
  • Updated: 11.10.2026 10:22

Impact

The /mcp-oauth/register endpoint accepted OAuth client registrations without authentication, allowing arbitrary redirect_uri values to be registered. When a user denies the MCP OAuth consent dialog, the handleDeny handler redirects the user to the registered redirect_uri without validation, enabling an open redirect to an attacker-controlled URL. An attacker can craft a phishing link and send it to a victim; if the victim clicks "Deny" on the consent page, they are silently redirected to an external site.

Patches

The issue has been fixed in n8n versions 1.123.32, 2.17.4, and 2.18.1. 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 network access to the n8n instance to prevent untrusted users from reaching the MCP OAuth endpoints.
  • Limit access to the n8n instance to fully trusted users only.

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

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
npm package n8n < 1.123.32, >= 2.18.0, < 2.18.1, >= 2.0.0, < 2.17.4 1.123.32, 2.18.1, 2.17.4

References

CVSS score 4.7/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N
Weakness (CWE)
CWE-601
Platform
npm
Package
n8n
Disclosed
29.04.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-f6x8-65q6-j9m9 - CC BY 4.0

Vulnerability history: n8n

All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (156) in the archive
Total entries
156
First → latest
05.2023 09.2026
Without a fix
1
Exploited in attacks
1

Severity breakdown

  • Critical 24
  • High 58
  • Medium 74

Disclosures per year

  1. 2023: 3
  2. 2024: 0
  3. 2025: 14
  4. 2026: 139
Severity:
  1. n8n has Open Redirect in MCP OAuth Consent Flow this entry
    Medium · 4.7 CVE-2026-42230 < 1.123.32, >= 2.18.0, < 2.18.1, >= 2.0.0, < 2.17.4 1.123.32, 2.18.1, 2.17.4
  2. High CVE-2026-86083 < 1.123.76, >= 2.38.0, < 2.38.2, >= 2.0.0, < 2.37.7 1.123.76, 2.38.2, 2.37.7
  3. High CVE-2026-86082 < 1.123.76, >= 2.38.0, < 2.38.2, >= 2.0.0, < 2.37.7 1.123.76, 2.38.2, 2.37.7
  4. High CVE-2026-86081 < 1.123.76, >= 2.38.0, < 2.38.2, >= 2.0.0, < 2.37.7 1.123.76, 2.38.2, 2.37.7
  5. High CVE-2026-86075 >= 2.38.0, < 2.38.2, < 2.37.7 2.38.2, 2.37.7
  6. High CVE-2026-86076 < 1.123.76, >= 2.38.0, < 2.38.2, >= 2.0.0, < 2.37.7 1.123.76, 2.38.2, 2.37.7
  7. High CVE-2026-72749 < 1.123.67, >= 2.32.0, < 2.32.1, >= 2.0.0-rc.0, < 2.31.5 1.123.67, 2.32.1, 2.31.5
  8. High CVE-2026-72762 < 1.123.67, >= 2.32.0, < 2.32.1, >= 2.0.0-rc.0, < 2.31.5 1.123.67, 2.32.1, 2.31.5
  9. High CVE-2026-72763 < 1.123.67, >= 2.32.0, < 2.32.1, >= 2.0.0-rc.0, < 2.31.5 1.123.67, 2.32.1, 2.31.5
  10. High CVE-2026-72774 < 1.123.67, >= 2.32.0, < 2.32.1, >= 2.0.0-rc.0, < 2.31.5 1.123.67, 2.32.1, 2.31.5
  11. High CVE-2026-72765 >= 2.32.0, < 2.32.1, < 2.31.5 2.32.1, 2.31.5
  12. High CVE-2026-72766 < 1.123.67, >= 2.32.0, < 2.32.1, >= 2.0.0-rc.0, < 2.31.5 1.123.67, 2.32.1, 2.31.5
  13. High CVE-2026-72767 < 1.123.67, >= 2.32.0, < 2.32.1, >= 2.0.0-rc.0, < 2.31.5 1.123.67, 2.32.1, 2.31.5
  14. High CVE-2026-72770 < 1.123.67, >= 2.32.0, < 2.32.1, >= 2.0.0-rc.0, < 2.31.5 1.123.67, 2.32.1, 2.31.5
  15. High CVE-2026-72771 >= 2.32.0, < 2.32.1, < 2.31.5 2.32.1, 2.31.5
  16. High CVE-2026-72772 >= 2.32.0, < 2.32.1, < 2.31.5 2.32.1, 2.31.5
  17. High CVE-2026-65016 < 1.123.64, >= 2.30.0, < 2.30.1, >= 2.0.0-rc.0, < 2.29.8 1.123.64, 2.30.1, 2.29.8
  18. High CVE-2026-65591 < 1.123.64, >= 2.30.0, < 2.30.1, >= 2.0.0-rc.0, < 2.29.8 1.123.64, 2.30.1, 2.29.8
  19. High CVE-2026-59208 >= 2.28.0, < 2.28.1, < 2.27.4 2.28.1, 2.27.4
  20. High CVE-2026-59207 >= 2.28.0, < 2.28.1, < 2.27.4 2.28.1, 2.27.4
  21. High CVE-2026-59206 < 1.123.61, >= 2.28.0, < 2.28.1, >= 2.0.0-rc.0, < 2.27.4 1.123.61, 2.28.1, 2.27.4
  22. High CVE-2026-59209 < 1.123.61, >= 2.28.0, < 2.28.1, >= 2.0.0-rc.0, < 2.27.4 1.123.61, 2.28.1, 2.27.4
  23. High CVE-2026-65592 < 1.123.64, >= 2.30.0, < 2.30.1, >= 2.0.0-rc.0, < 2.29.8 1.123.64, 2.30.1, 2.29.8
  24. High CVE-2026-65597 < 1.123.64, >= 2.30.0, < 2.30.1, >= 2.0.0-rc.0, < 2.29.8 1.123.64, 2.30.1, 2.29.8
  25. High CVE-2026-65598 < 1.123.64, >= 2.30.0, < 2.30.1, >= 2.0.0-rc.0, < 2.29.8 1.123.64, 2.30.1, 2.29.8
  26. High CVE-2026-65015 >= 2.30.0, < 2.30.1, < 2.29.8 2.30.1, 2.29.8
  27. High · 7.7 CVE-2026-54304 < 1.123.55, >= 2.26.0, < 2.26.1, >= 2.0.0-rc.0, < 2.25.7 1.123.55, 2.26.1, 2.25.7
  28. High · 10.0 CVE-2026-54309 >= 2.26.0, < 2.26.2, < 2.25.7 2.26.2, 2.25.7
  29. High · 9.9 CVE-2026-54305 < 1.123.55, >= 2.26.0, < 2.26.2, >= 2.0.0-rc.0, < 2.25.7 1.123.55, 2.26.2, 2.25.7
  30. High · 9.6 CVE-2026-54307 < 1.123.55, >= 2.26.0, < 2.26.2, >= 2.0.0-rc.0, < 2.25.7 1.123.55, 2.26.2, 2.25.7
  31. High · 7.6 CVE-2026-54302 < 1.123.55, >= 2.26.0, < 2.26.2, >= 2.0.0-rc.0, < 2.25.7 1.123.55, 2.26.2, 2.25.7
  32. High · 8.5 CVE-2026-54312 < 2.24.0 2.24.0
  33. High · 7.6 CVE-2026-54301 < 1.123.55, >= 2.26.0, < 2.26.2, >= 2.0.0-rc.0, < 2.25.7 1.123.55, 2.26.2, 2.25.7
  34. High · 8.5 CVE-2026-49444 < 1.123.48, >= 2.22.0, < 2.22.4, >= 2.0.0-rc.0, < 2.21.8 1.123.48, 2.22.4, 2.21.8
  35. High · 8.1 CVE-2026-45732 < 1.123.43, >= 2.21.0, < 2.21.1, >= 2.0.0-rc.0, < 2.20.7 1.123.43, 2.21.1, 2.20.7
  36. High · 9.0 CVE-2026-44792 < 1.123.43, >= 2.21.0, < 2.21.1, >= 2.0.0-rc.0, < 2.20.7 1.123.43, 2.21.1, 2.20.7
  37. Critical · 9.9 CVE-2026-44791 < 1.123.43, >= 2.21.0, < 2.22.1, >= 2.0.0-rc.0, < 2.20.7 1.123.43, 2.22.1, 2.20.7
  38. Critical · 8.8 CVE-2026-44790 < 1.123.43, >= 2.21.0, < 2.22.1, >= 2.0.0-rc.0, < 2.20.7 1.123.43, 2.22.1, 2.20.7
  39. Critical · 9.9 CVE-2026-44789 < 1.123.43, >= 2.21.0, < 2.22.1, >= 2.0.0-rc.0, < 2.20.7 1.123.43, 2.22.1, 2.20.7
  40. Critical · 9.9 CVE-2026-42232 >= 2.18.0, < 2.18.1, >= 2.17.0, < 2.17.4, < 1.123.32 2.18.1, 2.17.4, 1.123.32
Show more (20) Showing 41 of 83

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