CVE-2026-42230
published 2026-05-04CVE-2026-42230: n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, the /mcp-oauth/register endpoint accepted OAuth client…
PriorityP432medium6.1CVSS 3.1
AVNACLPRNUIRSCCLILAN
EPSS
0.18%
7.9th percentile
n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, 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. This issue has been patched in versions 1.123.32, 2.17.4, and 2.18.1.
Affected
9 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| n8n-io | n8n | < 1.123.32 | 1.123.32 |
| n8n-io | n8n | — | — |
| n8n-io | n8n | — | — |
| n8n | n8n | < 1.123.32 | 1.123.32 |
| n8n | n8n | — | — |
| n8n | n8n | >= 0 < 1.123.32 | 1.123.32 |
| n8n | n8n | >= 2.0.0 < 2.17.4 | 2.17.4 |
| n8n | n8n | >= 2.17.0 < 2.17.4 | 2.17.4 |
| n8n | n8n | >= 2.18.0 < 2.18.1 | 2.18.1 |
CVSS provenance
nvdv3.16.1MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
nvdv4.05.1MEDIUMCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:L/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
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VulDB
n8n-io n8n up to 1.123.31/2.17.3/2.18.0 /mcp-oauth/register redirect_uri (GHSA-f6x8-65q6-j9m9)
vuldb·2026-05-04·CVSS 5.1
CVE-2026-42230 [MEDIUM] n8n-io n8n up to 1.123.31/2.17.3/2.18.0 /mcp-oauth/register redirect_uri (GHSA-f6x8-65q6-j9m9)
A vulnerability, which was classified as problematic, has been found in n8n-io n8n up to 1.123.31/2.17.3/2.18.0. This affects an unknown part of the file /mcp-oauth/register. This manipulation of the argument redirect_uri causes open redirect.
This vulnerability appears as CVE-2026-42230. The attack may be initiated remotely. There is no available exploit.
It is advisable to upgrade the affected component.
GHSA
n8n has Open Redirect in MCP OAuth Consent Flow
ghsa·2026-04-29
CVE-2026-42230 [MEDIUM] CWE-601 n8n has Open Redirect in MCP OAuth Consent Flow
n8n has Open Redirect in MCP OAuth Consent Flow
## 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 poss
No detection rules found.
No public exploits indexed.
2026-05-04
Published