CVE-2026-21533: Microsoft Windows privilege escalation in Remote Desktop Services

CVE-2026-21533 · Severity: critical · CVSS 7.8 · Exploited in the wild · Published 2026-02-10

A security vulnerability has been identified in Microsoft Windows Remote Desktop Services, a component used to access computers and servers remotely. An attacker who already has basic access to a system could exploit this flaw to gain full administrative control. This vulnerability is reportedly being used in active attacks, making it a high priority for remediation to prevent unauthorized system takeovers.

Technologies: Microsoft Windows. Vendors: Microsoft.

Quick answers

Is CVE-2026-21533 exploited in the wild?
Yes. CVE-2026-21533 is known to be exploited in the wild, first recorded on 10 February 2026. Treat it as urgent.
How severe is CVE-2026-21533?
Critical severity, with a CVSS score of 7.8, published 10 February 2026.
Which products and versions are affected?
Microsoft Windows Windows 10, Windows 11, Windows Server 2012, 2016, 2019, 2022, 2025.
Is there a fix for CVE-2026-21533?
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-2026-21533 attacked?
It is attacked with local access, in an operating system.
Am I affected by CVE-2026-21533?
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 local privilege escalation vulnerability (CWE-269) exists in Microsoft Windows Remote Desktop Services due to improper privilege management. An attacker with low-privileged local access can exploit this flaw to gain SYSTEM-level privileges on the affected host. The attack vector is local and requires no user interaction, though the attacker must already have an authenticated foothold on the system. This vulnerability has been added to the CISA Known Exploited Vulnerabilities (KEV) catalog, indicating active exploitation in the wild. Microsoft has released security updates to address this issue across supported versions of Windows and Windows Server.

Affected products

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

Timeline

  • 2026-02-10: disclosed
  • 2026-02-10: advisory
  • 2026-02-10: kev added: Added to CISA KEV catalog due to active exploitation.
  • 2026-02-10: exploited

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