---
id: CVE-2026-118678
title: >-
  n8n before 2.41.4 and 2.42.1 Prototype Pollution DoS via Workflow History
  Compaction
summary: >-
  n8n before 2.41.4 and 2.42.x before 2.42.1 contains a prototype pollution
  vulnerability that allows low-privileged users to alter built-in object
  behaviour by saving workflows with specially named connection keys. Attackers
  can add keys …
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H'
cvssSource: cna
cwe:
  - CWE-1321
vendor: n8n-io
product: n8n
affected:
  - n8n < 2.41.4
  - n8n >= 2.42.0 < 2.42.1
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-29T15:28:50.969331Z'
published: '2026-10-28'
updated: '2026-10-29'
sourceUpdated: '2026-10-29T20:54:29.021Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-118678'
references:
  - url: 'https://github.com/n8n-io/n8n/security/advisories/GHSA-fvv4-gmv9-xqf5'
    label: GitHub Security Advisory (GHSA-fvv4-gmv9-xqf5)
  - url: >-
      https://www.vulncheck.com/advisories/n8n-before-2.41.4-and-2.42.1-prototype-pollution-dos-via-workflow-history-compaction
    label: >-
      VulnCheck Advisory: n8n before 2.41.4 and 2.42.1 Prototype Pollution DoS
      via Workflow History Compaction
tags:
  - cve.org
epss: 0.00293
epssPercentile: 0.2207
ingestedAt: '2026-10-29T15:37:07.548Z'
---

## Overview

n8n before 2.41.4 and 2.42.x before 2.42.1 contains a prototype pollution vulnerability that allows low-privileged users to alter built-in object behaviour by saving workflows with specially named connection keys. Attackers can add keys such as __proto__ to workflow connections, which the periodic history compaction task processes, causing logins and writes to fail with server errors.

## Affected

- `n8n < 2.41.4`
- `n8n >= 2.42.0 < 2.42.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.