CVE-2026-42969

What it actually does

This vulnerability is a local information disclosure flaw in Windows Push Notifications caused by use of an uninitialized resource. A low-privileged, authenticated local attacker can trigger the vulnerable component without user interaction and potentially read sensitive information from memory or another local resource that should not be exposed to that user. The CVSS vector indicates local access is required, exploitation complexity is low, privileges are required, and the impact is limited to confidentiality with no direct integrity or availability impact.

Why it matters to the business

Successful exploitation could expose sensitive data present on an affected Windows workstation or server, such as application data, notification-related content, process memory fragments, tokens, configuration details, or other locally accessible secrets depending on what the uninitialized resource contains at runtime. This is not currently listed in CISA KEV, has no known ransomware association, and has low EPSS with no 30-day upward trend, so broad internet-scale exploitation is unlikely; however, it can still be useful to an attacker who already has local access and is trying to escalate the value of that foothold or gather data for later compromise.

How an attack unfolds

An attacker must first obtain the ability to run code or commands as a local authenticated user on an affected Windows system. They then interact with the Windows Push Notifications functionality in a way that causes the vulnerable code path to use an uninitialized resource. Because the resource was not properly initialized before use, the component may return or expose data that originated from a prior allocation, process context, notification object, or other local state. The attacker collects the disclosed information and reviews it for credentials, tokens, user data, internal configuration, session material, or other sensitive content. This vulnerability is most likely to be chained with another weakness or post-compromise activity rather than used as an initial access vector.

How to fix it

Apply the Microsoft security update or cumulative update that addresses this vulnerability for all affected Windows versions, including Windows 10, Windows 11, Windows Server 2016, Windows Server 2019, Windows Server 2022, and Windows Server 2025. Because no fixed package versions were provided in the input, use the vendor advisory, Microsoft Update, Windows Update for Business, WSUS, Microsoft Configuration Manager, or equivalent patch-management tooling to identify the applicable June 2026 or later cumulative update for each supported operating system release. Prioritize shared workstations, multi-user systems, remote desktop hosts, developer workstations, jump hosts, and servers where local low-privileged access is more likely. Where immediate patching is not possible, reduce exposure by limiting interactive logon rights, removing unnecessary local users, enforcing least privilege, monitoring local code execution, and restricting untrusted users from running arbitrary scripts or binaries.

How to confirm the fix worked

Confirm that each affected Windows system has installed the Microsoft cumulative update that supersedes the vulnerable build for its operating system version. Validate through centralized patch inventory, Windows Update history, vulnerability scanning, endpoint management reports, or by comparing OS build and update level against the Microsoft advisory. For representative systems, verify that the host has rebooted after patch installation if required. Re-scan patched assets with an authenticated vulnerability scanner and confirm that the vulnerability is no longer reported. For compensating controls, confirm that local interactive access is restricted to authorized users and that endpoint controls block or alert on untrusted local tools and scripts.

Typical attack path

1. Gain local authenticated access to an affected Windows workstation or server through valid credentials, malware execution, phishing, or another vulnerability.
2. Execute a local tool, script, or proof-of-concept that interacts with Windows Push Notifications and triggers the uninitialized resource condition.
3. Capture any data returned or leaked by the vulnerable component.
4. Analyze the disclosed information for secrets, user data, process details, configuration values, or other material useful for lateral movement or privilege escalation.
5. Use any recovered sensitive information to support follow-on activity, such as credential theft, session abuse, reconnaissance, or targeting of additional systems.

How to detect it

There are no reliable public, vulnerability-specific indicators of compromise for this issue based on the provided information, and exploitation may not leave a unique artifact because it is a local information disclosure condition. To assess possible prior exploitation, review endpoint detection and response telemetry, Windows Security logs, PowerShell logs, Sysmon logs, and application execution records for suspicious local tools or scripts run by low-privileged users on affected systems. Focus on events before patch installation involving unusual interaction with notification-related Windows components, unexpected execution from user-writable directories, command shells spawned by user applications, or local reconnaissance activity following suspicious process execution. Useful log sources include Windows Security Event ID 4688 process creation, Sysmon Event ID 1 process creation, PowerShell Script Block Logging Event ID 4104, EDR command-line telemetry, file creation events in temporary and user profile directories, and authentication logs showing unusual local or RDP sessions. Since exploitation requires local authenticated access, correlate suspicious process execution with logon events, privilege changes, credential access alerts, and subsequent lateral movement indicators. Absence of these artifacts does not prove non-exploitation; memory-only disclosure may leave no durable forensic trace.

What your security team should do

• Inventory all affected Windows client and server versions and identify systems missing the relevant Microsoft cumulative update.
• Prioritize remediation on multi-user Windows systems, RDP-accessible hosts, privileged administration workstations, jump servers, and endpoints used by high-value users.
• Deploy the vendor update through standard Windows patch-management channels and verify successful installation and reboot completion.
• Treat this as a post-compromise data exposure risk: review endpoint telemetry for suspicious local execution on systems where patching is delayed.
• Limit local logon rights, remove unnecessary local administrators, and enforce least privilege to reduce the number of users who could exploit the flaw.
• Monitor for abnormal access to Windows notification components or local proof-of-concept execution, especially by non-administrative users.
• Because EPSS is low, exploit maturity is listed as none, and the vulnerability is not in KEV, handle under normal patch SLAs unless affected systems are high-value, shared, or already exposed to untrusted local users.