n8n Prototype Pollution Vulnerability Leads to Remote Code Execution

A critical prototype pollution vulnerability (CVE-2026-33696) exists within the GSuiteAdmin node of n8n, a workflow automation platform. This flaw enables an authenticated user, possessing the ability to create or modify workflows, to inject arbitrary values into the Object.prototype. By crafting malicious parameters during node configuration, an attacker can effectively overwrite properties of the base JavaScript object. Successful exploitation leads to remote code execution (RCE) on the n8n instance, potentially compromising sensitive data and systems. The vulnerability affects n8n versions prior to 2.14.1, 2.13.3, and 1.123.27. Defenders should prioritize upgrading n8n instances to patched versions to mitigate this risk.

Attack Chain

1. An attacker authenticates to an n8n instance with permissions to create or modify workflows.
2. The attacker crafts a malicious workflow that includes a GSuiteAdmin node.
3. Within the GSuiteAdmin node’s configuration, the attacker injects a specially crafted parameter designed to trigger prototype pollution.
4. The crafted parameter manipulates the Object.prototype by assigning attacker-controlled values.
5. The n8n application processes the workflow, executing the GSuiteAdmin node with the polluted prototype.
6. The prototype pollution leads to the execution of arbitrary code within the n8n instance’s context.
7. The attacker gains control of the n8n instance, enabling further malicious activities.
8. The attacker can now use the compromised instance to access sensitive data, pivot to other systems, or deploy further attacks.

Impact

Successful exploitation of this vulnerability allows an attacker to achieve remote code execution on the n8n instance. This grants the attacker complete control over the application and the underlying server. Potential consequences include data theft, deployment of ransomware, lateral movement to other systems within the network, and disruption of critical business processes automated by n8n workflows. The number of affected organizations depends on the prevalence of vulnerable n8n instances.

Recommendation

• Upgrade n8n to versions 2.14.1, 2.13.3, or 1.123.27 or later to patch CVE-2026-33696.
• Limit workflow creation and editing permissions to fully trusted users only, as described in the advisory.
• Disable the XML node by adding n8n-nodes-base.xml to the NODES_EXCLUDE environment variable, as described in the advisory.