n8n: Legacy Expression Evaluator Sanitizer Bypass Leads to Authenticated Code Execution

HighCVE-2026-65591 · Published Jul 22, 2026

## Impact The legacy expression evaluator's computed-member sanitizer can be bypassed by an authenticated user with workflow create or modify permissions. Successful exploitation grants the attacker host-level code execution as the n8n process. The legacy expression engine is the default engine in affected versions. ## Patches The issue has been fixed in n8n versions 1.123.64, 2.29.8, and 2.30.1. Users should upgrade to one of these versions or later to remediate the vulnerability. ## Workarounds If upgrading is not immediately possible, administrators should consider the following temporary mitigations: - Restrict n8n instance access to fully trusted users only. - Switch to the non-legacy expression engine by setting `N8N_EXPRESSION_ENGINE=vm`. These workarounds do not fully remediate the risk and should only be used as short-term mitigation measures.