CVE-2026-42970

What it actually does

This is a local information disclosure vulnerability in the Windows Push Notifications component caused by use of an uninitialized resource. An attacker who already has valid local user-level execution on an affected Windows system may be able to cause the component to return or expose memory or resource data that should not be accessible to that user. The CVSS vector indicates local access, low attack complexity, low privileges required, no user interaction, and high confidentiality impact, with no direct integrity or availability impact.

Why it matters to the business

Successful exploitation could allow an attacker with an existing foothold to obtain sensitive local information from Windows systems, potentially including data useful for credential theft, session discovery, application context, or follow-on privilege escalation. This flaw is not known to be exploited in the wild, is not in the CISA KEV catalog, has no known ransomware association, and has a low, flat EPSS score, so it is generally a patch-management priority rather than an emergency response item. Because it affects broadly deployed Windows client and server versions, organizations should still remediate through normal Microsoft security update cycles to reduce post-compromise exposure.

How an attack unfolds

An attacker first needs local code execution as an authorized, low-privileged user on an affected Windows host. From that position, the attacker invokes Windows Push Notifications functionality in a way that triggers the uninitialized resource condition. If exploitation succeeds, the component may disclose information from memory or another local resource that should not be exposed to the attacker's security context. The attacker can then inspect the disclosed data for secrets, tokens, user or application context, or other information that helps expand access, evade detection, or prepare additional attacks. There is currently no public indication of mature exploit code, known active exploitation, KEV listing, or named threat actor use for this vulnerability.

How to fix it

Apply the Microsoft security update that addresses this vulnerability for all affected Windows versions, including Windows 10, Windows 11, Windows Server 2012, Windows Server 2016, Windows Server 2019, Windows Server 2022, and Windows Server 2025. Where exact fixed build numbers are managed internally through Windows Update, WSUS, Microsoft Configuration Manager, Intune, or another patch platform, verify that the applicable cumulative update for the June 2026 or later security release level is installed. If immediate patching is not possible, reduce risk by limiting local interactive access, enforcing least privilege, preventing untrusted code execution, monitoring for suspicious local process activity, and prioritizing systems where lower-privileged users can run arbitrary code. Disabling or restricting unnecessary notification-related functionality may reduce exposure in some scenarios, but should not be treated as a substitute for applying the vendor fix.

How to confirm the fix worked

Confirm that affected Windows assets have installed the relevant Microsoft cumulative security update that includes the fix. Validate through centralized patch inventory, Windows Update history, WSUS or endpoint-management compliance reports, and operating system build verification. On representative systems, confirm the Windows version and build are at or above the organization-approved fixed baseline for the applicable release channel. Re-scan with authenticated vulnerability scanning after patch deployment to confirm the vulnerability is no longer reported. For systems that cannot be patched, document the exception, confirm compensating controls are in place, and monitor for local suspicious activity involving Windows Push Notifications services or unusual processes running under standard user accounts.

Typical attack path

1. Gain valid local user-level access to an affected Windows workstation or server through phishing, stolen credentials, malware execution, or another initial-access technique.
2. Run code locally under the compromised user's context.
3. Interact with Windows Push Notifications functionality to trigger the uninitialized resource behavior.
4. Capture any disclosed local information returned by the vulnerable component.
5. Analyze the disclosed information for credentials, tokens, application data, user activity, or environment details.
6. Use the recovered information to support lateral movement, privilege escalation, persistence, or further data access.

How to detect it

This vulnerability is a local information disclosure issue and may not produce a distinctive network signature or reliable exploit artifact. Focus detection on evidence of prior local compromise and suspicious interaction with Windows notification components. Useful log sources include Windows Security logs for local logon and process-creation activity, Sysmon process creation and file access telemetry, Microsoft Defender for Endpoint advanced hunting data, EDR telemetry, PowerShell logs, and application/service logs related to Windows notification services. Look for unusual processes running from user-writable paths that interact with svchost-hosted notification services, abnormal activity around Windows Push Notifications services such as WpnService or per-user WpnUserService instances, local reconnaissance immediately after suspicious execution, and attempts to dump or inspect process memory. Because there are no public exploit-specific indicators, absence of these artifacts does not prove non-exploitation; prioritize timeline analysis around initial compromise events, unknown binaries, script execution, and suspicious local enumeration.

What your security team should do

• Patch affected Windows client and server systems through the standard Microsoft security update process, prioritizing shared workstations, jump hosts, remote desktop servers, developer workstations, and servers where non-administrative users can execute code.
• Use authenticated vulnerability scanning and endpoint-management compliance reporting to identify systems missing the relevant cumulative update.
• Treat exploitation as a post-compromise risk: review controls that prevent local code execution, including application control, endpoint protection, least privilege, and credential theft protections.
• Monitor for unusual local processes interacting with notification-related Windows services, especially when launched from user-writable directories or recently delivered by email, browser downloads, or scripting tools.
• Because no active exploitation or ransomware use is currently known and EPSS is low and stable, schedule remediation according to normal security patch SLAs unless local risk factors justify acceleration.
• For high-value systems that cannot be patched promptly, restrict interactive logon, reduce exposed user sessions, and increase endpoint telemetry collection until remediation is complete.