CVE-2026-23944 is a critical authentication bypass vulnerability classified under CWE-306 (Missing Authentication for Critical Function) affecting the Arcane application, an interface used to manage Docker containers, images, networks, and volumes. In versions prior to 1.13.2, the environment proxy middleware component responsible for handling API requests to remote environments (/api/environments/{id}/...) fails to enforce authentication before proxying these requests. When the environment ID specified in the request does not correspond to a local environment, the middleware forwards the request to the remote environment agent and attaches a manager-held agent token, regardless of whether the original requestor is authenticated. This design flaw allows unauthenticated attackers to perform sensitive operations on remote Docker environments, including listing containers, streaming logs, and other agent endpoints. The vulnerability can lead to unauthorized access and control over remote Docker resources, resulting in potential data leakage, unauthorized changes to containerized applications, or disruption of services. The vulnerability is exploitable remotely without any authentication or user interaction, increasing its risk profile. The issue was addressed in Arcane version 1.13.2 by enforcing proper authentication checks before proxying requests to remote environment agents.

For European organizations utilizing Arcane to manage Docker environments, this vulnerability poses significant risks. Attackers can remotely access and manipulate containerized environments without authentication, potentially exposing sensitive data processed or stored within containers. Unauthorized control over containers could lead to deployment of malicious workloads, lateral movement within networks, or disruption of critical services. Industries relying heavily on containerization, such as finance, healthcare, and manufacturing, may face operational downtime, regulatory compliance violations (e.g., GDPR breaches due to data exposure), and reputational damage. The ability to stream logs and list containers also facilitates reconnaissance and further exploitation. Given the widespread adoption of Docker and container orchestration in Europe, the vulnerability could impact cloud service providers, managed service providers, and enterprises running hybrid or multi-cloud environments. The lack of known exploits in the wild currently reduces immediate risk but does not diminish the urgency for remediation due to the ease of exploitation and high potential impact.

European organizations should immediately upgrade Arcane installations to version 1.13.2 or later, where the authentication bypass has been fixed. Until patching is possible, organizations should restrict network access to the Arcane management interface, limiting it to trusted internal networks or VPNs to reduce exposure. Implement network segmentation to isolate Docker management interfaces from general user access. Monitor logs for unusual or unauthenticated API requests targeting /api/environments endpoints. Employ Web Application Firewalls (WAFs) or API gateways to enforce authentication and rate limiting on Arcane interfaces. Conduct thorough audits of Docker environments for unauthorized changes or suspicious activity. Additionally, review and tighten access controls on remote environment agents and consider disabling proxying features if not required. Incorporate Arcane vulnerability checks into regular vulnerability management and container security assessments to ensure timely detection of outdated versions.