CVE-2026-86078: n8n Prototype Pollution — Fix

Description

n8n is an open source workflow automation platform. Prior to 2.37.7 and 2.38.2, the Instance AI workflow summary used node names and connection keys from stored workflows as ordinary object keys. A workflow submitted through the REST API could contain __proto__ or constructor, causing nested writes to reach Object.prototype in the main n8n process and disrupt later requests. The affected function is summarizeWorkflowStructure in packages/@n8n/instance-ai/src/tools/workflows/summarize-workflow.ts. This issue is fixed in versions 2.37.7 and 2.38.2.

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CVSS v3.1 Score

6.5

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0033

Probability of exploitation

0.26%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-1321 CWE-1321

Affected Products

Vendor	Product	Versions
n8n	n8n	< 2.37.7
n8n	n8n	2.38.0 — 2.38.2

References

Advisories & Patches

https://github.com/n8n-io/n8n/security/advisories/GHSA-679f-58pq-4v2c

Other References

https://github.com/n8n-io/n8n/releases/tag/[email protected] https://github.com/n8n-io/n8n/releases/tag/[email protected]

Frequently Asked Questions

What is CVE-2026-86078? +

n8n is an open source workflow automation platform. Prior to 2.37.7 and 2.38.2, the Instance AI workflow summary used node names and connection keys from stored workflows as ordinary object keys. A workflow submitted through the REST API could contain __proto__ or constructor, causing nested writes to reach Object.prototype in the main n8n process and disrupt later requests. The affected function is summarizeWorkflowStructure in packages/@n8n/instance-ai/src/tools/workflows/summarize-workflow.ts. This issue is fixed in versions 2.37.7 and 2.38.2. It has a CVSS v3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-86078? +

CVE-2026-86078 has a CVSS v3.1 score of 6.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0033, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-86078? +

CVE-2026-86078 affects products from n8n, specifically: n8n. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-86078? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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