Vulnerability · Published Oct 28, 2026 · Assigned by VulnCheck

CVE-2026-118678n8n before 2.41.4 and 2.42.1 Prototype Pollution DoS via Workflow History Compaction

High 7.1

In plain English

A high-severity prototype pollution in n8n from n8n-io. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities).

Severity (CVSS 3.1)7.1High

Exploit odds (30 days)0.3%top 77.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
n8n-io	n8n	0 – before 2.41.4
n8n-io	n8n	2.42.0 – before 2.42.1

Weakness: CWE-1321 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H

References

GitHub Security Advisory (GHSA-fvv4-gmv9-xqf5) vendor-advisory
VulnCheck Advisory: n8n before 2.41.4 and 2.42.1 Prototype Pollution DoS via Workflow History Compaction third-party-advisory