CVE-2026-77077: n8n before 1.123.69 Remote Code Execution via EventEmitter Prototype Pollution

Severity: high (CVSS 7.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-20 · updated 2026-09-01
Weakness: CWE-94

Description

n8n versions before 1.123.69, 2.33.4, and 2.34.1 contain a JavaScript task runner VM sandbox escape. The runner's prototype-freezing routine covers globalThis functions but not internal module constructors such as EventEmitter, allowing an authenticated user with Code node access to exploit prototype pollution to execute arbitrary commands within the runner container. Because the polluted prototype is a process-wide object, the corruption persists across other tenants' Code node executions on the same shared runner. On v1.x instances without task runners enabled, Code node JavaScript runs directly in the main n8n process, where the impact could be higher.

Affected products

n8n-io n8n: before 1.123.69; from 2.33.0 before 2.33.4; 2.34.0 — fixed in 1.123.69, 2.33.4

How to fix

Upgrade to a fixed version: n8n-io n8n 1.123.69, 2.33.4. Check the vendor advisory for mitigations.

References

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