CVE-2026-70019 in Windows
Summary
by MITRE • 09/09/2026
Windows hard link in Windows Compressed Folder allows an unauthorized attacker to disclose information over a network.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability described involves a flaw within the implementation of compressed folders, specifically regarding how they handle hard links on Microsoft Windows operating systems. This issue stems from improper access control checks when interacting with file system objects that have been linked via the NTFS hard link mechanism. When an attacker creates or manipulates these hard links in conjunction with compressed folder operations, it can lead to a situation where sensitive information is exposed beyond its intended scope. The core technical flaw lies in the failure of the compression utility to properly validate permissions before reading data through the hard-linked path, effectively bypassing standard security boundaries that would normally restrict access to specific files or directories.
From an operational perspective, this vulnerability allows for unauthorized disclosure of information over a network if the compromised system is accessible remotely or if malicious actors can influence local file operations that are subsequently accessed via network shares. An attacker could potentially read contents of restricted files by exploiting the hard link feature to traverse into areas they should not have access to. This type of flaw falls under the category of path traversal and improper privilege management, as it exploits a gap in how the operating system resolves paths for compressed archives compared to standard file operations. The impact is primarily confidentiality-related, leading to potential exposure of sensitive data such as configuration files, user documents, or internal application secrets depending on what resources are accessible through the manipulated links.
In terms of industry standards and classification frameworks, this vulnerability aligns with CWE-20 Improper Input Validation regarding how file paths and link targets are processed before access is granted. It also relates to CWE-732 Incorrect Permission Assignment for Critical Resource because the underlying issue is a failure in assigning or checking permissions correctly during the archive extraction or viewing process. Furthermore, within the MITRE ATT&CK framework, this behavior can be associated with T1083 File and Directory Discovery, where an adversary uses techniques to enumerate sensitive files on a system. The exploitation vector often involves local access initially but can escalate if combined with other vulnerabilities that allow remote code execution or network-based interaction with the file system.
Mitigation strategies for this vulnerability primarily involve ensuring that all Windows systems are updated with the latest security patches provided by Microsoft, as such flaws in core components like compressed folders are typically addressed through cumulative updates. Administrators should also enforce strict access control lists on directories containing sensitive information to limit who can create hard links or modify file permissions. Additionally, disabling unnecessary features related to archive handling if they are not required for business operations can reduce the attack surface. Organizations must maintain a robust patch management process and monitor for any indicators of compromise that suggest an attacker is attempting to exploit file system manipulation techniques to gain unauthorized access to critical data assets.