Executive brief
n8n is a workflow automation platform that allows users to build and execute complex business processes. A vulnerability in n8n's Form node allows unauthenticated attackers to inject and execute arbitrary expressions through specially crafted form submissions. In combination with a separate sandbox escape, this could enable remote code execution on the n8n instance, potentially compromising the entire workflow automation system and any data it processes.
Technical details
This is a second-order expression injection vulnerability (CWE-94, CWE-95) in n8n's Form nodes caused by improper handling of user-supplied input in form fields. The vulnerability occurs when a form field is prefixed with an equals sign (=), which n8n treats as an expression marker and causes double-evaluation of the field content. An unauthenticated attacker can submit crafted form data containing malicious n8n expressions to trigger arbitrary expression evaluation. Exploitation requires a specific workflow configuration where a downstream Form node renders user-provided input preceded by an equals sign. While the expression injection alone is limited to data within the n8n expression context, chaining this vulnerability with a sandbox escape could lead to remote code execution. Patches are available in versions 1.123.22, 2.9.3, and 2.10.1.
Affected products
- n8n n8n before 1.123.22; 2.0.0 before 2.9.3; 2.10.0 before 2.10.1
Timeline
- 2026-02-25: disclosed: Advisory published
- 2026-02-25: patched: Patches released in versions 1.123.22, 2.9.3, and 2.10.1