CVE-2026-78453 in Windows
Summary
by MITRE • 09/09/2026
Integer underflow (wrap or wraparound) in Microsoft Windows SCSI Class System File allows an unauthorized attacker to disclose information over a network.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified involves an integer underflow within the Microsoft Windows SCSI Class System file, specifically affecting how data structures are processed during input validation routines. This flaw arises when the system fails to properly verify that arithmetic operations result in non-negative values before allocating memory or copying buffers. In this specific context, a malicious actor can craft a specially designed request containing manipulated numerical parameters that trigger an underflow condition. When the integer wraps around from its minimum negative value to a large positive maximum due to insufficient boundary checks, it leads to incorrect calculations regarding buffer sizes or array indices. This miscalculation allows for out-of-bounds memory access patterns that deviate significantly from intended operational boundaries.
From a technical perspective, this issue falls under the category of CWE-192 Integer Underflow which can lead to CWE-787 Out-of-bounds Write and potentially CWE-20 Improper Input Validation. The root cause lies in the lack of rigorous type checking and range validation for user-supplied data before it is used in critical system functions. Because the SCSI class driver handles communication between software applications and storage devices, any manipulation of these internal counters can have profound implications for system stability and security integrity. An attacker exploiting this flaw does not necessarily need local access but may leverage network-facing services or interfaces that expose vulnerable code paths to remote interaction vectors.
The operational impact of this vulnerability is primarily centered on information disclosure over a network. By triggering the underflow condition, an unauthorized actor can read sensitive data from kernel memory spaces that are typically protected from user-mode applications. This could include credentials, encryption keys, internal system states, or other confidential information residing in adjacent memory blocks. The ability to exfiltrate such data remotely significantly escalates the severity of the threat landscape, as it enables stealthy reconnaissance and potential pivot points for further attacks within a networked environment. It undermines the confidentiality guarantees provided by Windows operating systems and exposes organizations to significant risks regarding intellectual property theft and compliance violations.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. The primary defense is applying the latest security patches released by Microsoft, which address these validation gaps in the SCSI class driver codebase. Organizations should ensure that all Windows endpoints are updated promptly through automated patch management systems to close this specific attack vector. Additionally, implementing network segmentation can limit exposure by restricting access to vulnerable services from untrusted networks. Security teams should also monitor for anomalous behavior indicative of exploitation attempts, such as unusual memory allocation patterns or unexpected data transfers originating from system processes involved in storage operations.
To prevent recurrence, developers must adhere strictly to secure coding standards that mandate explicit validation of all input values before arithmetic operations are performed. Tools like static analysis scanners and fuzzing frameworks should be integrated into the software development lifecycle to detect integer overflow and underflow conditions early. Furthermore, enabling advanced protection mechanisms such as Kernel Address Space Layout Randomization (KASLR) and Data Execution Prevention can mitigate the impact by making it harder for attackers to predict memory layouts or execute arbitrary code even if information disclosure occurs. Continuous monitoring of ATT&CK techniques related to unauthorized access and data exfiltration will help in detecting potential exploitation activities in real-time environments.