CVE-2026-21510: Microsoft Windows Shell protection mechanism failure

CVE-2026-21510 · Severity: critical · CVSS 8.8 · Exploited in the wild · Published 2026-02-10

A security flaw has been identified in the Windows Shell, the graphical interface used to manage files and applications on Microsoft Windows. This vulnerability allows an attacker to bypass built-in security protections, potentially leading to unauthorized access or control over a user's system. This issue is particularly serious as it has been observed being actively exploited in the wild.

Technologies: Microsoft Windows. Vendors: Microsoft.

Quick answers

Is CVE-2026-21510 exploited in the wild?
Yes. CVE-2026-21510 is known to be exploited in the wild, first recorded on 10 February 2026. Treat it as urgent.
How severe is CVE-2026-21510?
Critical severity, with a CVSS score of 8.8, published 10 February 2026.
Which products and versions are affected?
Microsoft Windows 10, 11, Server 2012, Server 2016, Server 2019, Server 2022, Server 2025.
Is there a fix for CVE-2026-21510?
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-2026-21510 attacked?
It is attacked over the network, in an operating system.
Am I affected by CVE-2026-21510?
Check whether you run Microsoft Windows. 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 protection mechanism failure (CWE-693) exists in the Microsoft Windows Shell component. The vulnerability is triggered over a network vector and requires minimal user interaction (UI:R), allowing an unauthenticated attacker to bypass security features and potentially achieve full system compromise (High Confidentiality, Integrity, and Availability impact). Affected versions include Windows 10, Windows 11, and various Windows Server editions. Microsoft has released security updates to address this flaw, which is currently listed in CISA's Known Exploited Vulnerabilities (KEV) catalog.

Affected products

  • Microsoft Windows 10, 11, Server 2012, Server 2016, Server 2019, Server 2022, Server 2025

Timeline

  • 2026-02-10: disclosed
  • 2026-02-10: advisory: Microsoft released vendor advisory and CISA added to KEV catalog
  • 2026-02-10: exploited: Confirmed active exploitation in the wild

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