The vulnerability identified as CVE-2026-25056 affects the open-source workflow automation platform n8n prior to versions 1.118.0 and 2.4.0. Specifically, it resides in the Merge node's SQL Query mode, where authenticated users with permissions to create or modify workflows can exploit an unrestricted file upload flaw (CWE-434) to write arbitrary files to the server's filesystem. This flaw is compounded by improper validation of file types and content, enabling attackers to upload malicious payloads that can be executed remotely, leading to remote code execution (RCE). The vulnerability also relates to CWE-693, indicating protection mechanisms are bypassed or insufficient. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H) highlights that the attack can be performed remotely over the network with low attack complexity, no user interaction, and only requires low privileges (authenticated user with workflow modification rights). The impact on confidentiality, integrity, and availability is high, as attackers can execute arbitrary code, potentially compromising the entire system and connected infrastructure. Although no public exploits have been observed, the vulnerability's nature and scoring suggest it is a critical risk. The issue has been addressed in versions 1.118.0 and 2.4.0, and users are strongly advised to upgrade. The vulnerability is particularly concerning for organizations relying on n8n for automating critical workflows, as an attacker could leverage this flaw to gain persistent access or disrupt operations.

For European organizations, the impact of CVE-2026-25056 is significant. Many enterprises and public sector entities use workflow automation platforms like n8n to streamline business processes, integrate services, and manage data flows. Exploitation could lead to unauthorized access to sensitive data, disruption of automated workflows, and full system compromise through remote code execution. This could result in data breaches, operational downtime, and potential regulatory non-compliance under GDPR due to loss of data confidentiality and integrity. The ability for an authenticated user with relatively low privileges to escalate to full system compromise increases insider threat risks and the impact of compromised credentials. Additionally, the attack vector does not require user interaction, making automated exploitation feasible once credentials are obtained. This vulnerability could also be leveraged as a foothold for lateral movement within networks, threatening broader organizational security. The critical nature of the flaw necessitates urgent remediation to prevent potential exploitation and associated financial, reputational, and legal damages.

European organizations should immediately upgrade all n8n instances to versions 1.118.0 or 2.4.0 or later to remediate this vulnerability. Until upgrades are applied, restrict workflow creation and modification permissions strictly to trusted administrators to limit the pool of users who can exploit the flaw. Implement strong authentication mechanisms, including multi-factor authentication (MFA), to reduce the risk of credential compromise. Monitor system logs and file system changes for unusual activity, particularly unexpected file writes in directories used by n8n. Employ network segmentation to isolate n8n servers from critical infrastructure and sensitive data stores. Consider deploying application-layer firewalls or runtime application self-protection (RASP) solutions to detect and block suspicious file upload or execution attempts. Regularly audit workflow configurations and user permissions to ensure adherence to the principle of least privilege. Finally, maintain up-to-date backups and incident response plans to quickly recover from potential compromises.