CVE-2026-40635 in PowerScale OneFS
Summary
by MITRE • 09/09/2026
Dell PowerScale OneFS versions 9.12.0.0 through 9.13.1.0 contain an Insecure Temporary File vulnerability. A low privileged remote attacker could potentially exploit this vulnerability, leading to denial of service and information tampering.
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Analysis
by VulDB Data Team • 09/09/2026
The identified security flaw resides within Dell PowerScale OneFS software versions ranging from 9.12.0.0 through 9.13.1.0, specifically affecting the handling of temporary files during system operations. This vulnerability is classified as an insecure temporary file creation issue, which fundamentally stems from a failure to properly secure transient data storage locations against unauthorized access or modification by processes with lower privilege levels than intended. In many enterprise storage environments, including those managed by OneFS, various background services and daemons frequently generate temporary files for intermediate processing tasks such as log rotation, configuration updates, or metadata synchronization. When these systems do not enforce strict permissions on the directories where these files are created, they become susceptible to race conditions and symlink attacks that allow lower-privileged users to intercept or manipulate data before it is consumed by higher-privilege processes.
From a technical perspective, this vulnerability aligns with Common Weakness Enumeration identifier CWE-377, which describes insecure temporary file creation. The core issue involves the use of predictable filenames or insufficient access controls on directories like /tmp or application-specific temp folders. An attacker operating under a low-privileged account can exploit these weaknesses by creating malicious files in advance that match the expected names of legitimate temporary files generated by system processes. By leveraging symbolic links or race conditions, the attacker can trick privileged services into writing sensitive data to locations controlled by the attacker or reading manipulated content from those same locations. This mechanism bypasses standard authentication and authorization checks because the exploitation relies on file system behavior rather than direct service interaction through network protocols that might have stricter validation layers.
The operational impact of this vulnerability is significant, primarily manifesting as a denial of service condition and potential information tampering. If an attacker successfully manipulates temporary files used by critical storage management services, they can cause those services to crash or behave unpredictably, leading to outages in the storage cluster's availability. This disruption affects data accessibility for connected clients and undermines the reliability guarantees provided by the PowerScale platform. Furthermore, the information tampering aspect poses a severe risk to data integrity. An attacker could alter configuration parameters stored temporarily during updates or inject malicious payloads into scripts executed with elevated privileges via these temporary files. Such actions could lead to unauthorized privilege escalation, where the low-privileged user gains control over system functions, potentially allowing them to exfiltrate sensitive metadata, modify access controls, or compromise other nodes within the cluster through lateral movement facilitated by the compromised state of the OneFS management interface.
This vulnerability is also relevant to MITRE ATT&CK techniques related to privilege escalation and persistence, particularly those involving file manipulation and abuse of system processes for execution. The ability to influence high-privilege operations through low-privileged inputs represents a classic path for escalating access within an organization's infrastructure. Security teams should recognize that even remote attackers with minimal initial access can leverage this flaw to disrupt services or alter critical configurations without needing direct write permissions to protected directories, relying instead on the system's trust in its own temporary file handling mechanisms.
To mitigate these risks, administrators must ensure that all systems running OneFS versions 9.12.0.0 through 9.13.1.0 are updated to a patched version released by Dell Technologies after this vulnerability was disclosed and addressed. Immediate patching is the most effective remediation strategy as it resolves the underlying code defects responsible for insecure file handling practices. In addition to applying updates, organizations should review their system hardening configurations to ensure that temporary directories have restrictive permissions set according to best practices, such as using sticky bits on shared temp folders to prevent users from deleting or renaming files owned by other users. Monitoring logs for unusual activity in temporary directory locations can also help detect exploitation attempts early. Regular audits of file permission settings and adherence to the principle of least privilege across all service accounts will further reduce the attack surface associated with insecure temporary file vulnerabilities, ensuring that even if similar flaws exist in future software versions, their exploitable impact is minimized through robust operational security controls.