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Exploited vulnerability · CISA KEV

Is CVE-2026-21533 exploited? Yes: in CISA KEV since 10 Feb 2026

Gociux · Microsoft Windows · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2026-21533, Microsoft Windows Improper Privilege Management Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 10 Feb 2026, the day it was published. It affects Microsoft Windows. If you run it, CISA's required action is: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

exploitedYesCISA KEV · 10 Feb 2026
ransomwareNot knownno confirmed use
EPSStop 10%more likely than most to be exploited
severity7.8CVSS 3.1 · high
US federal due3 Mar 2026BOD 22-01 deadline

What it is

Microsoft Windows Remote Desktop Services contains an improper privilege management vulnerability that could allow an authorized attacker to elevate privileges locally.

VendorMicrosoft (391 exploited CVEs in KEV)
ProductWindows
VulnerabilityMicrosoft Windows Improper Privilege Management Vulnerability
WeaknessCWE-269
Published10 Feb 2026
Added to KEV10 Feb 2026
Reported by (CNA)microsoft

What to do

  1. Check whether you run it. Look for Windows in your asset inventory, including appliances and cloud images. Stack check lists every exploited Microsoft CVE at once.
  2. Apply the fix. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
  3. If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 10 Feb 2026.
  4. Get told next time. Email alerts when CISA adds a CVE for Microsoft.

Other exploited CVEs in Windows

References

Questions

Is CVE-2026-21533 being exploited?

Yes. CISA added CVE-2026-21533 to the Known Exploited Vulnerabilities catalog on 10 Feb 2026, which means there is reliable evidence of exploitation in the wild.

Is CVE-2026-21533 used in ransomware attacks?

CISA does not list known ransomware use for it. That can change, and exploitation alone is reason to fix it first.

How do I fix CVE-2026-21533?

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Check Microsoft's advisory for the fixed versions, and if you can't patch quickly, restrict access to the affected Windows and watch it for signs of compromise.

Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in February 2026 · Microsoft scorecard · act-now radar.

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