CVE-2026-86078 PUBLISHED

n8n: Prototype Pollution via Workflow Structure Summary Can Lead to Denial of Service

Assigner: GitHub_M
Reserved: 04.09.2026 Published: 08.09.2026 Updated: 08.09.2026

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.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS Score: 6

Product Status

Vendor n8n-io
Product n8n
Versions
  • Version < 2.37.7 is affected
  • Version >= 2.38.0, < 2.38.2 is affected

References

Problem Types

  • CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') CWE