CVE-2026-78451 in Windows
Summary
by MITRE • 09/09/2026
Untrusted pointer dereference in Microsoft Windows SCSI Class System File allows an unauthorized attacker to elevate privileges with a physical attack.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified as an untrusted pointer dereference within the Microsoft Windows SCSI Class System file represents a critical security flaw that compromises the integrity of kernel-mode operations. This specific defect arises from improper validation of memory addresses passed by user-space applications or hardware interfaces before they are utilized for data access. In the context of operating system architecture, the SCSI class driver serves as an intermediary between storage devices and the Windows kernel, handling complex input/output control requests. When this component fails to adequately verify that a pointer provided in such a request is valid, mapped correctly within the process address space, or belongs to a trusted source, it creates a pathway for memory corruption. The core technical flaw lies in the lack of rigorous bounds checking and ownership verification during the processing of SCSI commands, allowing an attacker to supply a maliciously crafted pointer that points to arbitrary kernel memory locations rather than legitimate buffers allocated by the system.
From an operational perspective, this vulnerability enables privilege escalation from a lower-privileged user context or even physical access scenarios to SYSTEM-level privileges within the Windows operating environment. An unauthorized actor who gains physical access to the machine can exploit this flaw through direct hardware interaction or via connected peripherals that support SCSI protocols. By sending specially crafted commands over interfaces such as Thunderbolt, USB storage controllers configured in passthrough mode, or other external storage devices, an attacker can trigger the untrusted pointer dereference. This action typically results in a buffer overflow or arbitrary write condition within kernel space, allowing the execution of arbitrary code with the highest level of system access. The impact is severe, as it grants full control over the operating system, enabling data exfiltration, persistence mechanisms installation, and complete compromise of confidentiality, integrity, and availability for all users on the affected machine.
This vulnerability aligns closely with Common Weakness Enumeration (CWE) categories such as CWE-94 Improper Control of Generation of Code or Command, specifically in contexts where untrusted input leads to unsafe memory operations, and more directly with CWE-125 Out-of-bounds Read if it results in information disclosure, or CWE-787 Out-of-bounds Write if it allows for code execution. In terms of the MITRE ATT&CK framework, this exploit technique falls under Tactic 06: Defense Evasion and Technique T1068 Exploitation for Privilege Escalation. It also relates to physical attack vectors described in tactics concerning peripheral device manipulation, where attackers leverage direct hardware access to bypass software-based security controls that are otherwise effective against remote network attacks. The reliance on physical proximity makes this a significant concern for environments handling sensitive data or operating in physically insecure locations.
Mitigation strategies must address both the technical flaw and the attack vector limitations. Microsoft has released patches updating the SCSI class system file to include rigorous validation checks for all pointers received from user-mode applications and hardware interfaces. Administrators should ensure that Windows systems are updated with the latest security updates provided by Microsoft, which specifically patch this kernel-level memory handling error. Beyond software remediation, physical access controls remain paramount since the vulnerability can be exploited via direct connection of malicious peripherals. Organizations should enforce strict policies regarding USB port usage, disable unnecessary external storage interfaces when not in use, and utilize hardware-based encryption or locking mechanisms to prevent unauthorized device attachment. Additionally, enabling Secure Boot and configuring BitLocker with TPM integration adds layers of protection that make it significantly harder for an attacker to execute arbitrary code even if they manage to exploit the memory corruption vulnerability, as these features restrict unsigned kernel drivers from loading during boot processes.