Prototype Pollution in N8n
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.
Vulnerability class: Prototype Pollution
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (47.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
- N8n
- N8n-Io N8n — versions < 2.37.7, >= 2.38.0, < 2.38.2
Weakness classification (CWE)
References
- github.com/n8n-io/n8n/security/advisories/GHSA-679f-58pq-4v2c (Mitigation, Vendor Advisory)
- github.com/n8n-io/n8n/releases/tag/n8n@2.37.7 (Release Notes)
- github.com/n8n-io/n8n/releases/tag/n8n@2.38.2 (Release Notes)
Frequently asked questions
- What is CVE-2026-86078?
- CVE-2026-86078 is a medium-severity vulnerability in N8n, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 6.5/10. Published 2026-09-08.
- How severe is CVE-2026-86078?
- Medium severity. CVSS v3 base score is 6.5 out of 10.