CVE-2026-86114 in Arcane
Summary
by MITRE • 09/05/2026
Arcane versions before 2.0.0 fail to properly restrict template operations, allowing default user role accounts to create, modify, and delete compose templates including instance-wide defaults. Attackers can inject malicious container configurations with privileged settings or host path mounts that execute with administrative privileges when deployed by administrators.
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Analysis
by VulDB Data Team • 09/05/2026
The vulnerability identified in Arcane versions prior to 2.0.0 represents a critical failure in access control mechanisms, specifically within the template management subsystem. This flaw stems from an insufficient restriction on operations performed by default user role accounts, which are typically intended for limited or read-only interactions with the system. Instead of enforcing strict boundaries between administrative and standard user privileges, the application allows these lower-privileged entities to execute create, modify, and delete actions on compose templates. These templates serve as blueprints for container deployments, often including instance-wide defaults that dictate how services are configured across the entire infrastructure. By permitting unauthorized modifications to these foundational configurations, the vulnerability undermines the principle of least privilege, a cornerstone of secure system architecture defined in CWE-269 regarding improper authorization.
The operational impact of this flaw is severe due to the nature of container orchestration environments where Arcane operates. When an attacker with default user privileges modifies or creates a compose template, they can inject malicious configurations into the deployment pipeline. Specifically, attackers can configure containers to run with elevated permissions by setting privileged flags or mounting sensitive host paths directly into the container environment. These settings allow processes running inside the compromised containers to interact with the underlying host operating system as if they were executing under administrative privileges. This capability effectively bypasses isolation mechanisms designed to contain potential breaches within individual containers, leading to a complete compromise of the host system and potentially other co-located workloads.
From an offensive security perspective, this vulnerability aligns closely with ATT&CK techniques related to container orchestration exploitation. The ability to inject malicious configurations corresponds to T1659, which involves abuse of cloud or infrastructure templates for initial access or persistence. Furthermore, the execution of commands within a privileged context maps directly to T1055, specifically Process Injection and Privilege Escalation via container escape mechanisms. Attackers can leverage these modified templates to establish persistent backdoors, exfiltrate data from sensitive host directories mounted into containers, or pivot laterally across the network by deploying compromised services that act as proxies for further attacks. The lack of validation on template content before deployment exacerbates this risk, allowing malicious payloads to be executed automatically when administrators deploy the affected configurations without realizing they have been tampered with.
Mitigating this vulnerability requires immediate updates to Arcane software versions 2.0.0 and later, where these access control restrictions are properly enforced. In environments where patching is not immediately feasible, organizations should implement strict network segmentation to limit communication between user-facing interfaces and container orchestration backends. Additionally, deploying runtime security solutions that monitor for privileged container execution or unauthorized host path mounts can provide an additional layer of defense. It is also critical to audit existing compose templates for any signs of tampering and to enforce role-based access control policies that strictly separate template creation rights from standard user accounts. Regularly reviewing and hardening default configurations against CWE-250, which addresses execution with unnecessary privileges, will further reduce the attack surface available to potential adversaries seeking to exploit this weakness.