SASTRA-ADI-WIGUNA-CVE-2026-21858-Holistic-Audit-n8n
Abstract
This document presents a deterministic technical reconstruction analysis of the CVE-2026-21858 vulnerability, internally designated as Ni8mare. This vulnerability carries a CVSS 10.0 (Critical) score and was identified within the Form Webhook node of the n8n automation platform. The flaw is a Content-Type Confusion vulnerability that enables unauthenticated attackers to perform arbitrary file reads, session forgery, and ultimately, Full Remote Code Execution (RCE) via the "Execute Command" node.
Fields of Study & Subjects
Web Application Security Vulnerabilities
Security and Verification in Computing
Information and Cyber Security
Publication details
- Journal / source
- Zenodo (CERN European Organization for Nuclear Research)
- Publication date
- 17 January 2026