n8n-io n8n up to 1.123.31/2.17.3/2.18.0 /mcp-oauth/register redirect_uri

Summaryinfo

A vulnerability, which was classified as problematic, was found in n8n-io n8n up to 1.123.31/2.17.3/2.18.0. This vulnerability affects unknown code of the file /mcp-oauth/register. Such manipulation of the argument redirect_uri leads to redirect. This vulnerability is traded as CVE-2026-42230. The attack may be launched remotely. There is no exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in n8n-io n8n up to 1.123.31/2.17.3/2.18.0. It has been rated as problematic. Affected by this issue is some unknown functionality of the file /mcp-oauth/register. The manipulation of the argument redirect_uri with an unknown input leads to a redirect vulnerability. Using CWE to declare the problem leads to CWE-601. A web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a Redirect. This simplifies phishing attacks. Impacted is integrity. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-42230 since 04/25/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1204.001 by the MITRE ATT&CK project.

Upgrading to version 1.123.32, 2.17.4 or 2.18.1 eliminates this vulnerability.

The vulnerability is also documented in the databases at EUVD (EUVD-2026-27100) and CERT Bund (WID-SEC-2026-1251). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Affected

• n8n n8n

Productinfo

Vendor

• n8n-io

Name

• n8n

Version

• 1.123.0
• 1.123.1
• 1.123.2
• 1.123.3
• 1.123.4
• 1.123.5
• 1.123.6
• 1.123.7
• 1.123.8
• 1.123.9
• 1.123.10
• 1.123.11
• 1.123.12
• 1.123.13
• 1.123.14
• 1.123.15
• 1.123.16
• 1.123.17
• 1.123.18
• 1.123.19
• 1.123.20
• 1.123.21
• 1.123.22
• 1.123.23
• 1.123.24
• 1.123.25
• 1.123.26
• 1.123.27
• 1.123.28
• 1.123.29
• 1.123.30
• 1.123.31
• 2.0
• 2.1
• 2.2
• 2.3
• 2.4
• 2.5
• 2.6
• 2.7
• 2.8
• 2.9
• 2.10
• 2.11
• 2.12
• 2.13
• 2.14
• 2.15
• 2.16
• 2.17
• 2.17.0
• 2.17.1
• 2.17.2
• 2.17.3
• 2.18.0

Website

• Product: https://github.com/n8n-io/n8n/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Discussion