Using string formatting and exception handling, an attacker may bypass n8n's python-task-executor sandbox restrictions and run arbitrary unrestricted Python code in the underlying operating system.
The vulnerability can be exploited via the Code block by an authenticated user with basic permissions and can lead to a full n8n instance takeover on instances operating under "Internal" execution mode.
If the instance is operating under the "External" execution mode (ex. n8n's official Docker image) - arbitrary code execution occurs inside a Sidecar container and not the main node, which significantly reduces the vulnerability impact.
Exploitability
AV:NAC:HPR:LUI:NScope
S:CImpact
C:HI:HA:H8.5/CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:HOther