Is CVE-2026-118678 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-118678 being exploited in the wild.

How severe is CVE-2026-118678?

High severity, with a CVSS score of 7.1, published 28 October 2026.

Which products and versions are affected?

N8n before 2.41.4 and 2.42.x before 2.42.1.

How is CVE-2026-118678 attacked?

It is attacked over the network, in a web application.

Am I affected by CVE-2026-118678?

Check whether you run N8n at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-118678: n8n prototype pollution in workflow history compaction

CVE-2026-118678 · Severity: high · CVSS 7.1 · Published 2026-10-28

n8n is a workflow automation platform that allows users to connect and chain applications. A low-privileged user can inject specially crafted workflow connections containing reserved JavaScript property names (like __proto__) that corrupt the application's internal object structure when the history compaction task runs, causing the service to fail logins and data writes. This results in a denial of service affecting all users of the affected instance.

Technologies: N8n. Vendors: N8n.

Quick answers

Is CVE-2026-118678 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-118678 being exploited in the wild.
How severe is CVE-2026-118678?: High severity, with a CVSS score of 7.1, published 28 October 2026.
Which products and versions are affected?: N8n before 2.41.4 and 2.42.x before 2.42.1.
Is there a fix for CVE-2026-118678?: Yes: fixed in n8n 2.41.4, 2.42.1 and later. Until then: Restrict n8n instance access to fully trusted users. Disable workflow history by setting N8N_WORKFLOW_HISTORY_ENABLED=false if not required. Audit existing workflows for nodes with reserved JavaScript property names (__proto__, constructor, prototype) in their connections and remove or rename them. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-118678 attacked?: It is attacked over the network, in a web application.
Am I affected by CVE-2026-118678?: Check whether you run N8n at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: n8n 2.41.4, 2.42.1 and later

Restrict n8n instance access to fully trusted users. Disable workflow history by setting N8N_WORKFLOW_HISTORY_ENABLED=false if not required. Audit existing workflows for nodes with reserved JavaScript property names (__proto__, constructor, prototype) in their connections and remove or rename them.

Technical details

A prototype pollution vulnerability exists in n8n's workflow history compaction routine, which diffs connection objects without sanitizing key names. An authenticated user with low privileges can save a workflow with connections bearing reserved property names; when the periodic compaction task processes these, it pollutes the JavaScript prototype chain. The attack requires network access and valid (low-privilege) credentials, and impacts availability and integrity but not confidentiality.

Affected products

n8n n8n before 2.41.4 and 2.42.x before 2.42.1

Timeline

2026-10-28: advisory
2026-10-14: patched

References

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