CVE-2026-59386 in Controller
Summary
by MITRE • 10/30/2026
A SpaceSupporter could improperly modify an application's start command and buildpack—actions requiring SpaceDeveloper privileges. This privilege escalation enables unauthorized retrieval of service credentials through malicious start commands or custom buildpacks.
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Analysis
by VulDB Data Team • 10/30/2026
The vulnerability described represents a critical authorization failure within the Cloud Foundry platform, specifically affecting users with SpaceSupporter roles who are granted permissions to manage application deployments without adequate restrictions on sensitive configuration parameters. In standard operational workflows, modifying an applications start command and associated buildpack is typically reserved for SpaceDevelopers or higher-privileged entities due to the potential impact on runtime behavior and security posture. However, when a SpaceSupporter can alter these fields, they bypass intended access controls that are designed to prevent unauthorized changes to how application code is executed and packaged. This misconfiguration allows lower-privilege users to inject arbitrary commands into the deployment lifecycle, effectively escalating their privileges by gaining control over the execution environment of applications within the space.
From a technical perspective, this flaw exploits the lack of proper authorization checks during the update process for application metadata. When an attacker modifies the start command, they can execute shell commands with the same permissions as the user running the Cloud Foundry Diego cell agent or the specific app instance runtime context. Similarly, manipulating buildpacks allows an attacker to introduce custom scripts that run during the staging phase of deployment. These stages occur before the application is fully isolated in its containerized environment, providing a window where arbitrary code execution can be achieved with elevated privileges relative to other space members. The core technical flaw lies in the API endpoint or UI logic failing to validate whether the requesting user possesses the necessary SpaceDeveloper role for these specific write operations, treating them as accessible to any authenticated member of the space who holds at least the Supporter designation.
The operational impact of this vulnerability is severe, primarily centering on unauthorized data exfiltration and potential full compromise of the underlying infrastructure. By injecting malicious start commands or custom buildpacks, an attacker can craft payloads designed to scrape environment variables from the application container. These variables frequently contain sensitive service credentials such as database passwords, API keys for third-party services, cloud provider access tokens, and internal network configuration details. Once these credentials are retrieved, they can be exfiltrated to a remote server controlled by the attacker. This leads directly to data breaches involving confidential business information and compromises the integrity of dependent systems that rely on those leaked credentials. Furthermore, if the buildpack modification allows for persistent backdoors or rootkit installation within the staging environment, it could lead to long-term persistence and lateral movement across the platform.
This vulnerability aligns with CWE-269 Improper Privilege Management, as it involves a user performing actions that exceed their assigned security clearance level due to insufficient enforcement of role-based access control rules. Additionally, the exploitation technique maps directly to MITRE ATT&CK techniques such as T1053 Scheduled Task/Job which relates to executing commands via system mechanisms like start scripts, and potentially T1608 Install Defacement Tool if custom buildpacks are used to alter application behavior persistently. The ability to retrieve service credentials also correlates with T1528 Steal Application Access Token or general credential harvesting techniques found in cloud environments.
To mitigate this risk, platform administrators must immediately review and tighten the role-based access control policies within their Cloud Foundry deployments. It is essential to ensure that only users explicitly assigned the SpaceDeveloper role can modify application start commands and buildpack configurations. This involves auditing existing space memberships and removing unnecessary permissions from Supporter accounts if they do not require deployment capabilities. Furthermore, implementing strict input validation on API endpoints handling these updates can prevent malformed or malicious payloads from being processed. Regular security audits of platform configuration should be conducted to verify that privilege boundaries are correctly enforced across all user roles. Additionally, enabling enhanced logging and monitoring for changes to application metadata can help detect unauthorized modification attempts in real time, allowing for rapid incident response before credentials are exfiltrated.