CVE-2026-126386

n8n before 1.123.89 Open Redirect via MCP OAuth Dynamic Client Registration

Published Nov 13, 2026 CVSS 4.0 · 5.1 Medium EPSS < 1% KEV · Not listed

Description

n8n before 1.123.89, 2.x before 2.45.5, 2.46.x before 2.46.1, and 3.x before 3.0.1 contains an open redirect vulnerability in the unauthenticated MCP OAuth dynamic client registration flow, which accepts arbitrary redirect_uri values via the /mcp-oauth/register endpoint. Attackers can send victims crafted /mcp-oauth/authorize URLs that redirect them to attacker-controlled sites before instance checks run, enabling phishing.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

n8n-io

n8n

unaffected

Version	Status	Constraints
`0`	affected	< 1.123.89
`1.123.89`	unaffected	—

n8n-io

n8n

unaffected

Version	Status	Constraints
`2.46.0`	affected	< 2.46.1
`2.46.1`	unaffected	—

n8n-io

n8n

unaffected

Version	Status	Constraints
`2.0.0`	affected	< 2.45.5
`2.45.5`	unaffected	—

n8n-io

n8n

unaffected

Version	Status	Constraints
`3.0.0`	affected	< 3.0.1
`3.0.1`	unaffected	—

No data.

No data available yet.

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

No advisories available

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction Active

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact Low

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact None

Integrity Impact Low

Availability Impact None

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.275% probability within 30 days)

Key SSVC decision points have not yet been added.

References

Link	Providers
https://github.com/n8n-io/n8n/security/advisories/GHSA-rc3w-8jc8-7x3w
https://www.vulncheck.com/advisories/n8n-before-1.123.89-open-redirect-via-mcp-oauth-dynamic-client-registration

History

Nov 13, 2026 9:45 AM Description updated. Title updated. First appearance in the feed. Weaknesses updated. Affected versions updated. Affected vendors updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		n8n before 1.123.89, 2.x before 2.45.5, 2.46.x before 2.46.1, and 3.x before 3.0.1 contains an open redirect vulnerability in the unauthenticated MCP OAuth dynamic client registration flow, which accepts arbitrary redirect_uri values via the /mcp-oauth/register endpoint. Attackers can send victims crafted /mcp-oauth/authorize URLs that redirect them to attacker-controlled sites before instance checks run, enabling phishing.
Title		n8n before 1.123.89 Open Redirect via MCP OAuth Dynamic Client Registration
First Time appeared		N8n N8n n8n
Weaknesses		CWE-601
CPEs		cpe:2.3:a:n8n:n8n::::::::
Vendors & Products		N8n N8n n8n
References		https://github.com/n8n-io/n8n/security/advisories/GHSA-rc3w-8jc8-7x3w https://www.vulncheck.com/advisories/n8n-before-1.123.89-open-redirect-via-mcp-oauth-dynamic-client-registration
Metrics		cvssV3_1 `{'score': 4.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N'}` cvssV4_0 `{'score': 5.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N'}`