CVE-2026-50473

What it actually does

This vulnerability is a local information disclosure flaw in Windows File Explorer. An attacker who already has valid local access can trigger File Explorer behavior that exposes sensitive information they should not be able to read. The CVSS vector indicates low attack complexity, local access, low privileges required, no user interaction, unchanged scope, high confidentiality impact, and no direct integrity or availability impact. It does not provide remote code execution or privilege escalation by itself, but it may expose data useful for follow-on activity.

Why it matters to the business

Successful exploitation could allow a low-privileged local user or malware running under a standard account to access sensitive information from an affected Windows workstation or server. The most likely business consequences are data exposure, loss of confidentiality, and increased risk of follow-on compromise if the disclosed information includes credentials, file metadata, document contents, paths, or other operational details. Because the issue affects many supported Windows client and server versions, remediation may require broad endpoint and server patch coverage, but it is not currently listed in CISA KEV and there is no reported ransomware use in the provided data.

How an attack unfolds

An attacker first needs local authenticated access to an affected Windows system, either as a legitimate low-privileged user or through malware already running in a user context. The attacker then interacts with Windows File Explorer or invokes the vulnerable File Explorer functionality in a way that causes sensitive information to be disclosed outside the intended authorization boundary. The disclosed information can be collected locally and used to understand file locations, user activity, sensitive documents, configuration details, or other data that may support credential theft, lateral movement, or targeted data theft. Because exploitation requires local access, this vulnerability is most relevant as a post-compromise or insider-risk issue rather than an internet-facing initial access vector.

How to fix it

Apply the Microsoft security update that addresses this vulnerability for all affected Windows versions, including Windows 10 1607, 1809, 21H2, 22H2; Windows 11 24H2, 25H2, 26H1; Windows Server 2016, 2019, 2022, and 2025. Because no explicit fixed build numbers were provided, use Microsoft Windows Update, Windows Server Update Services, Microsoft Configuration Manager, Intune, or the Microsoft Update Catalog to deploy the latest cumulative security updates released for the affected platforms. Where immediate patching is not possible, reduce exposure by limiting local interactive access, enforcing least privilege, restricting unnecessary Remote Desktop or console access, monitoring unusual local File Explorer activity, and ensuring sensitive files are protected with appropriate access controls and encryption. Mitigations should be treated as temporary because the vulnerability is in a core Windows component.

How to confirm the fix worked

Confirm that each affected Windows endpoint and server has installed the Microsoft cumulative update that includes the fix for this vulnerability. Validate through centralized patch management compliance reports, Windows Update history, installed hotfix inventory, or vulnerability scanning that maps operating system build and patch level to this vulnerability. On individual systems, review Settings > Windows Update > Update history, or use PowerShell commands such as Get-HotFix and operating system build checks to confirm the latest security update is installed. Vulnerability scanners should no longer report the issue after patching and rebooting where required. Also validate that standard users cannot reproduce the sensitive information disclosure behavior after remediation.

Typical attack path

1. Gain local authenticated access to an affected Windows workstation or server using a standard user account or already-deployed malware.
2. Identify that the system is running an affected Windows version and has not received the relevant security update.
3. Trigger the vulnerable Windows File Explorer information disclosure behavior locally.
4. Collect the exposed sensitive information from the local session, process output, UI artifact, cache, temporary location, or related system artifact depending on the exploit technique.
5. Use the disclosed information to support follow-on actions such as locating sensitive files, harvesting credentials or tokens if exposed, improving situational awareness, or planning lateral movement.

How to detect it

There are no universal public exploit artifacts or product-specific indicators in the provided data, and local information disclosure vulnerabilities often leave limited direct evidence. Focus detection on signs of suspicious local activity around File Explorer and sensitive file discovery. Relevant log sources include Windows Security event logs, Sysmon or EDR process telemetry, PowerShell logs, file access auditing, Remote Desktop logon events, and endpoint protection alerts. Look for low-privileged users launching explorer.exe in unusual contexts, repeated access attempts to sensitive directories, abnormal file enumeration, interactive logons to systems the user does not normally access, suspicious child processes spawned from Explorer, and discovery commands executed before or after File Explorer activity. Investigate whether any exposed information was subsequently used for credential access, lateral movement, or data collection. Useful Windows events may include logon events, object access events where auditing is enabled, process creation events, and share access events on servers.

• explorer.exe
• Event ID 4688
• Event ID 4624
• Event ID 4634
• Event ID 4663
• Event ID 5140
• Event ID 5145
• Sysmon Event ID 1
• Sysmon Event ID 11
• powershell.exe
• cmd.exe /c dir
• whoami /all
• net user
• net localgroup
• nltest /domain_trusts
• quser
• qwinsta

What your security team should do

• Prioritize patch deployment across affected Windows clients and servers, with higher priority for shared workstations, jump hosts, Remote Desktop servers, developer systems, file servers, and systems that process sensitive data.
• Use endpoint management tooling to inventory affected Windows versions and confirm installation of the latest cumulative security updates.
• Review local user, Remote Desktop, and administrative access rights to reduce the number of users who can interactively access high-value systems.
• Monitor for suspicious local enumeration behavior, unusual File Explorer launches, abnormal access to sensitive directories, and post-compromise discovery activity on Windows systems.
• Treat alerts involving this vulnerability as potential post-compromise activity because exploitation requires local authenticated access.
• Harden sensitive data storage with least-privilege file permissions, BitLocker or equivalent disk encryption, and credential protection controls.
• If sensitive information exposure is suspected, investigate whether the disclosed data could enable credential compromise, lateral movement, or regulatory notification obligations.