CVE-2026-50434

What it actually does

This is a local information disclosure vulnerability in Windows Push Notifications. An attacker who already has local, low-privileged access can abuse the affected Windows notification components to disclose sensitive information that should not be accessible to that user or security context. The flaw does not provide remote code execution, privilege escalation, data modification, or denial of service, but the CVSS vector indicates high confidentiality impact because exposed notification content or related data may include sensitive application, account, message, or operational information.

Why it matters to the business

Successful exploitation could allow a low-privileged local attacker to read sensitive information exposed through Windows notification handling, potentially including business messages, application alerts, user activity details, or other confidential notification data. This can create privacy, compliance, and investigative risk, especially on shared workstations, virtual desktops, jump hosts, administrative workstations, and servers where multiple users or service contexts may be present. The vulnerability is not currently listed in CISA KEV, has no reported ransomware association, and exploit maturity is listed as none, so urgency is lower than actively exploited issues; however, affected Windows 10, Windows 11, Windows Server 2022, and Windows Server 2025 systems should still be patched through normal security update cycles.

How an attack unfolds

An attacker first obtains local access to an affected Windows system, such as through a standard user account, malware running with user privileges, or access to a shared endpoint. Because the vulnerability requires local access and low privileges, the attacker does not need to trick another user or exploit a network-facing service directly. The attacker then interacts with Windows Push Notifications components or notification-related local data in a way that bypasses the intended access boundary. If successful, the attacker can disclose notification information or related sensitive data belonging to another context or otherwise not authorized for that user. The attacker may then use the exposed information for reconnaissance, credential or token targeting if sensitive secrets are present in notifications, user profiling, social engineering, or follow-on attacks.

How to fix it

Apply the Microsoft security update that addresses this vulnerability for all affected supported Windows versions, including Windows 10 21H2, Windows 10 22H2, Windows 11 24H2, Windows 11 25H2, Windows 11 26H1, Windows Server 2022, and Windows Server 2025. Where exact fixed build numbers are not available, use Windows Update, Microsoft Update Catalog, WSUS, Intune, Configuration Manager, or the organization’s endpoint management tooling to deploy the latest cumulative security updates released after the vulnerability publication date. Prioritize shared endpoints, VDI images, administrative workstations, kiosks, multi-user systems, and servers where local access by different users or service accounts is possible. If immediate patching is not possible, reduce exposure by limiting local interactive access, enforcing least privilege, restricting untrusted code execution, monitoring access to notification storage, and disabling unnecessary notification-related functionality where operationally acceptable.

How to confirm the fix worked

Confirm that affected Windows systems have installed the Microsoft cumulative security update that includes the fix by checking Windows Update history, endpoint management compliance reports, or installed hotfix/build inventory. Validate coverage across all listed operating system versions, including gold images, offline images, VDI base images, and servers. Review whether systems still run unsupported or unpatched Windows builds. Where feasible, verify that notification-related local files and services are no longer accessible across unintended user boundaries after patching. For exposure assessment, inventory systems with Windows Push Notifications services present and prioritize those with multiple local users, shared administrative use, or sensitive notification-generating applications.

Typical attack path

1. Gain local access to an affected Windows endpoint or server with a low-privileged account or process.
2. Identify whether Windows Push Notifications components and notification data are present and active on the system.
3. Trigger or interact with the vulnerable notification handling path to bypass intended access controls.
4. Read sensitive notification content, metadata, or related locally stored information that should not be available to the attacker.
5. Use the disclosed information for reconnaissance, privacy invasion, targeted phishing, credential/token hunting, or preparation for further compromise.

How to detect it

Because this is a local information disclosure issue and there is no public exploit maturity reported, exploitation may leave limited or no definitive forensic artifacts. Detection should focus on suspicious local access to Windows notification storage and unusual interaction with notification services by non-standard processes. Useful log and telemetry sources include Microsoft Defender for Endpoint device file and process events, Sysmon file creation/access telemetry if configured, Windows Security object access auditing events such as 4656 and 4663 when auditing is enabled for notification paths, PowerShell logs, EDR process lineage, and the Microsoft-Windows-PushNotifications-Platform operational log if available. Look for low-privileged processes, scripts, command shells, remote management tools, or unknown binaries accessing user notification database files under local app data paths. Also review whether access was followed by credential discovery, browser data access, clipboard collection, screen capture, archive creation, or outbound transfer, as the disclosed information may be used in a broader intrusion chain.

• %LOCALAPPDATA%\Microsoft\Windows\Notifications\wpndatabase.db
• \AppData\Local\Microsoft\Windows\Notifications\wpndatabase.db
• Microsoft-Windows-PushNotifications-Platform/Operational
• WpnUserService
• WpnService
• wpndatabase.db

What your security team should do

• Deploy the applicable Microsoft cumulative security updates to all affected Windows 10, Windows 11, Windows Server 2022, and Windows Server 2025 systems.
• Prioritize patching for shared workstations, VDI pools, administrative workstations, jump hosts, kiosks, and multi-user servers.
• Inventory systems that allow local interactive access by non-administrative users and verify they are included in patch compliance reporting.
• Restrict local logon rights and remove unnecessary standard-user access from sensitive systems.
• Monitor for unusual access to Windows notification database files or notification-related directories by non-standard processes.
• Review endpoint telemetry for suspicious local reconnaissance following possible notification data access.
• Ensure applications do not place secrets, one-time codes, access tokens, or highly sensitive content in desktop notifications where avoidable.
• Include updated Windows base images in imaging, VDI, and server provisioning pipelines.