CVE-2026-27577 is a critical vulnerability in the n8n open source workflow automation platform, identified as CWE-94: Improper Control of Generation of Code ('Code Injection'). The flaw exists in the expression evaluation mechanism used within workflow parameters, where an authenticated user with permissions to create or modify workflows can inject crafted expressions that lead to unintended execution of system commands on the host machine running n8n. This vulnerability affects multiple versions of n8n prior to 2.10.1, 2.9.3, and 1.123.22. The root cause is insufficient sanitization and control over code generation during expression evaluation, allowing malicious payloads to be executed at the system level. Exploitation does not require user interaction beyond authentication and leverages legitimate workflow editing capabilities, making it a potent attack vector. The vulnerability was disclosed and patched promptly, with the vendor recommending immediate upgrades to the fixed versions. In environments where immediate patching is not feasible, administrators are advised to restrict workflow creation and editing permissions strictly to trusted users and deploy n8n in a hardened environment with minimal OS privileges and network restrictions to contain potential exploitation impact. The CVSS 4.0 base score of 9.4 reflects the vulnerability's critical severity, considering its network attack vector, low complexity, no required user interaction, and high impact on confidentiality, integrity, and availability.

The impact of CVE-2026-27577 is severe for organizations using the n8n platform. Successful exploitation allows an authenticated user to execute arbitrary system commands on the host, potentially leading to full system compromise, data exfiltration, lateral movement within the network, and disruption of automated workflows. Since n8n is often integrated into critical business processes for automation, attackers could manipulate workflows to cause operational failures or inject malicious activities. The vulnerability undermines confidentiality, integrity, and availability of affected systems. Organizations relying on n8n for automation in cloud, on-premises, or hybrid environments face risks of unauthorized access and control over their infrastructure. The ease of exploitation by any user with workflow modification rights increases the threat surface, especially in environments with weak access controls. Although no known exploits are reported in the wild yet, the critical nature and public disclosure necessitate urgent remediation to prevent potential attacks.

To mitigate CVE-2026-27577, organizations should immediately upgrade n8n to versions 2.10.1, 2.9.3, or 1.123.22 or later, where the vulnerability is fully patched. Until upgrades can be applied, restrict workflow creation and editing permissions strictly to fully trusted and vetted users to minimize the risk of malicious expression injection. Deploy n8n in a hardened environment by running it with the least privilege principle, limiting operating system permissions and capabilities to reduce the impact of any potential exploitation. Network segmentation and firewall rules should be applied to restrict access to the n8n host, preventing attackers from leveraging compromised systems for lateral movement. Additionally, implement monitoring and alerting for unusual workflow changes or system command executions originating from n8n processes. Regularly audit user permissions and workflow configurations to detect unauthorized modifications. Consider using containerization or sandboxing techniques to isolate n8n runtime environments further. These layered defenses help reduce risk while planning and executing the upgrade.