n8n, an open source workflow automation platform, contains a prototype pollution flaw in the XML Node that allows an authenticated user with workflow creation or editing rights to manipulate JavaScript prototypes. By altering prototypes, the attacker can chain prototype pollution with other nodes to achieve arbitrary code execution on the host. This weakness is categorized as CWE‑1321 and can compromise the confidentiality, integrity, and availability of the system.

The vulnerability affects n8n versions older than 1.123.32, 2.17.4, and 2.18.1 across all deployments. Any install of v1.x before 1.123.32 or v2.x before 2.17.4 (or before 2.18.1) is susceptible when XML Node functionality is enabled.

The CVSS score of 9.4 indicates a critical severity, and the absence of an EPSS rating means the exploitation probability is currently unknown but the flaw is not yet catalogued in CISA’s KEV list. Because the attack requires authentication, only users with workflow editing privileges can initiate the exploit; however, once achieved, the effect is system‑wide remote code execution.