CVE-2026-85165

n8n versions before 2.36.2 contain an expression sandbox bypass (CWE-95) in which free identifiers appearing in spread, computed-key, switch-case, or class-extension positions resolve against process globals instead of staying confined to the expression sandbox. An authenticated user with workflow-edit permission can trigger the flaw by evaluating a crafted expression, mutating host objects so that the changes persist process-wide until the n8n process is restarted. An attacker gains tampering with the automation host, with integrity and availability impact rated High and confidentiality impact Low, for a CVSS 4.0 score of 7.2 (High). All self-hosted n8n deployments running versions prior to 2.36.2 are affected; the data does not state the status of vendor-managed cloud tenants, so self-hosted operators are the primary population at risk. No public proof-of-concept is known, the flaw is not in CISA KEV, and EPSS estimates only a 0.3% probability of exploitation in the next 30 days, so exploitation is not currently known to be occurring.

What to do: Upgrade self-hosted n8n to version 2.36.2 or later. Until patched, restrict workflow-edit permissions to trusted users and review workflows that use spread, computed-key, switch-case, or class-extension expressions; restart the n8n process after upgrading to clear any host objects mutated by prior expressions.