CVE-2026-21533 KEV
7.8
HIGH · CVSS 3.1 · EPSS 4.1% (pctl 90)
Patch first
On CISA KEV — known exploited in the wild, due 2026-03-03.
Description
Improper privilege management in Windows Remote Desktop allows an authorized attacker to elevate privileges locally.
Scoring
| CVSS | 7.8 (HIGH, v3.1) |
|---|---|
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| EPSS | 4.13% — more likely to be exploited than 90% of all CVEs |
| Weakness | CWE-269 |
| On CISA KEV | yes — remediate by 2026-03-03 |
| Public exploit | none known |
| Published | 2026-02-10 |
| Last modified | 2026-06-17 |
CISA KEV
| Name | Microsoft Windows Improper Privilege Management Vulnerability |
|---|---|
| Added | 2026-02-10 |
| Due | 2026-03-03 |
| Vendor / product | Microsoft / Windows |
| Ransomware use | none reported |
Affected (13)
| Vendor | Product |
|---|---|
| microsoft | windows 10 1607 |
| microsoft | windows 10 1809 |
| microsoft | windows 10 21h2 |
| microsoft | windows 10 22h2 |
| microsoft | windows 11 23h2 |
| microsoft | windows 11 24h2 |
| microsoft | windows 11 25h2 |
| microsoft | windows server 2012 |
| microsoft | windows server 2016 |
| microsoft | windows server 2019 |
| microsoft | windows server 2022 |
| microsoft | windows server 2022 23h2 |
| microsoft | windows server 2025 |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21533
- https://www.vicarius.io/vsociety/posts/cve-2026-21533-detection-script-privilege-escalation-vulnerability-in-windows-remote-desktop
- https://www.vicarius.io/vsociety/posts/cve-2026-21533-mitigation-script-privilege-escalation-vulnerability-in-windows-remote-desktop
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21533
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