Description

Dell Command Update (DCU), versions prior to 5.7.1, contain a Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability. A low privileged attacker with local access could potentially exploit this vulnerability, leading to Elevation of Privileges.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.8",
  "pubDate": "2026-08-19T15:17:10.417Z",
  "pubdate": "2026-08-19T15:17:10.417Z",
  "executiveSummary": "Dell Command Update (DCU), in versions prior to 5.7.1, contains a Time-of-check Time-of-use (TOCTOU) race condition vulnerability. This security flaw enables a locally authenticated, low-privileged attacker to execute malicious manipulations of file operations or system states, ultimately leading to an Elevation of Privileges (EoP) on the targeted system.\nThe root cause stems from a synchronization flaw where a security validation (the check phase) is separated in time from the actual resource utilization (the use phase). During this temporal window, an adversary can manipulate the target file or resource, bypassing security boundaries.\nSuccessful exploitation requires local access to the target endpoint, meaning the attacker must already possess an interactive session or the ability to execute code locally with limited privileges. Because Dell Command Update frequently executes tasks with elevated system privileges to manage firmware, drivers, and BIOS updates, successfully winning the race condition allows the attacker to inherit these high privileges.\nThe risk implication is severe, as local privilege escalation typically grants the attacker complete control over the operating system, facilitating persistence, credential theft, and lateral movement within the network. Mitigation requires immediate updating of the affected product to version 5.7.1 or later.",
  "technicalDetails": "The vulnerability resides within Dell Command Update (DCU) versions prior to 5.7.1, specifically in components or helper processes that perform privileged file system operations or resource access checks. The fundamental software defect is a Time-of-check Time-of-use (TOCTOU) race condition.\nFrom an authentication and network exposure perspective, this vulnerability requires local access. The attack surface is not exposed remotely over the network. The attacker must possess low-privileged local user credentials or code execution capabilities on the host system to initiate the attack sequence.\nThe exploitation mechanism relies on the asynchronous handling of system resources where a privileged DCU process validates the permissions, existence, or path of a file or object (Time-of-Check) before subsequently reading, writing, or executing that same object (Time-of-Use).\nThe step-by-step attack flow proceeds as follows: First, the low-privileged attacker identifies a scheduled task, background service, or user-initiated operation within Dell Command Update that interacts with the file system using elevated privileges. Second, the attacker predicts or monitors the exact moment the privileged DCU process performs a security validation on a target file path or temporary directory. Third, leveraging concurrent execution threads, the attacker rapidly swaps the validated resource with a symbolic link, hard link, or malicious file just before the application performs the operational 'use' phase. Fourth, because the security check was already completed, the privileged process acts upon the maliciously substituted resource.\nThrough this race condition manipulation, the application may be tricked into overwriting critical system files, granting unauthorized file access, or executing arbitrary code within the context of the high-privileged service account executing the DCU task.\nThe post-exploitation impact of this vulnerability is an Elevation of Privileges (EoP). By successfully executing the TOCTOU attack, the low-privileged attacker transitions their security context to that of the privileged process running the update utility, which often operates with administrative or SYSTEM-level privileges. This grants the adversary full control over the underlying operating system."
}