Is CVE-2026-42991 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-42991 being exploited in the wild.

How severe is CVE-2026-42991?

High severity, with a CVSS score of 7.8, published 9 June 2026.

Is there a fix for CVE-2026-42991?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-42991 attacked?

It is attacked with local access, in an operating system.

Am I affected by CVE-2026-42991?

Check whether you run Microsoft Windows Push Notifications. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-42991: Microsoft Windows Push Notifications privilege escalation via race condition

CVE-2026-42991 · Severity: high · CVSS 7.8 · Published 2026-06-09

A security vulnerability exists in the Windows Push Notification service, which handles real-time alerts and updates for applications. An attacker who already has limited access to a computer could exploit this flaw to gain full administrative control over the system. This could allow them to view sensitive data, install malicious software, or disrupt business operations.

Technologies: Microsoft Windows Push Notifications. Vendors: Microsoft.

Quick answers

Is CVE-2026-42991 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-42991 being exploited in the wild.
How severe is CVE-2026-42991?: High severity, with a CVSS score of 7.8, published 9 June 2026.
Which products and versions are affected?: Microsoft Windows Push Notifications.
Is there a fix for CVE-2026-42991?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-42991 attacked?: It is attacked with local access, in an operating system.
Am I affected by CVE-2026-42991?: Check whether you run Microsoft Windows Push Notifications. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A race condition (CWE-362) exists in the Windows Push Notifications service due to improper synchronization when accessing shared resources. This flaw can lead to a use-after-free (CWE-416) scenario, which an attacker can leverage to execute code with elevated privileges. The attack requires local access and is characterized by high complexity, as the attacker must successfully time the concurrent execution to trigger the synchronization error. If successful, the attacker can bypass security boundaries and gain SYSTEM-level access.

Affected products

Microsoft Windows Push Notifications

Timeline

2026-06-09: disclosed
2026-06-09: advisory

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-42991

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.