CVE-2026-118678

High

Description

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.

SeverityHigh

CVSS7.1

Exploit probability—

ProductN8n

PublishedOct 28, 2026

First seenNov 4, 2026

Weakness typeCWE-1321Prototype pollution

How to fix

Update

n8n-io n8n2.41.4, 2.42.1 or later

Vendor advisories

github.com/n8n-io/n8n/security/advisories/GHSA-fvv4-gmv9-xqf5

Affected products

Product	Affected versions	Fixed in
n8n-io n8n	v < 2.41.4, 2.42.0 ≤ v < 2.42.1	2.41.4, 2.42.1

Check your version

Choose the product and enter the version you run to see whether it falls in the affected range.

In the Intelligence 360 plan

Attack Surface Management

See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.