GHSA-f6x8-65q6-j9m9
MEDIUMGHSA-f6x8-65q6-j9m9 is a medium-severity (CVSS 4.7) vulnerability in n8n. O3 Security confirms whether GHSA-f6x8-65q6-j9m9 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
n8n has Open Redirect in MCP OAuth Consent Flow
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
n8nnpmDescription
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 Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | n8n | all versions | 1.123.32 |
| 📦npm | n8n | ≥ 2.18.0&&< 2.18.1 | 2.18.1 |
| 📦npm | n8n | ≥ 2.0.0&&< 2.17.4 | 2.17.4 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for n8n. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update n8n to 1.123.32 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-f6x8-65q6-j9m9 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-f6x8-65q6-j9m9 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-f6x8-65q6-j9m9. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-f6x8-65q6-j9m9 in your dependencies?
O3 detects GHSA-f6x8-65q6-j9m9 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.