What is CVE-2026-42231?

CVE-2026-42231 is a high-severity vulnerability in N8n, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 8.8/10. Published 2026-05-04.

How severe is CVE-2026-42231?

High severity. CVSS v3 base score is 8.8 out of 10.

Is CVE-2026-42231 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Prototype Pollution in N8n

CVE-2026-42231

n8n is an open source workflow automation platform. Prior to versions 1.123.32, 2.17.4, and 2.18.1, a flaw in the xml2js library used to parse XML request bodies in n8n's webhook handler allowed prototype pollution via a crafted XML payloa…

Vulnerability class: Prototype Pollution

EPSS: 0.004 (61.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Affected products

N8n — versions 2.18.0
N8n-io N8n — versions < 1.123.32, >= 2.17.0, < 2.17.4, >= 2.18.0, < 2.18.1

Weakness classification (CWE)

CWE-1321 — Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution)

Public proof-of-concept exploits

rudSarkar/CVE-2026-42231

References

https://github.com/n8n-io/n8n/security/advisories/GHSA-q5f4-99jv-pgg5 (x_refsource_CONFIRM, Vendor Advisory)

Frequently asked questions

What is CVE-2026-42231?: CVE-2026-42231 is a high-severity vulnerability in N8n, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 8.8/10. Published 2026-05-04.
How severe is CVE-2026-42231?: High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2026-42231 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.