Vulnerability report

Trusted Third Party Report Confirmed Confidence In CISA KEV

CVE-2026-21533

Windows Remote Desktop Services Elevation of Privilege Vulnerability

Microsoft / Windows 10 Version 1607 · affected before 10.0.14393.8868

Watch CVE-2026-21533 Browse KEV feed
Severity
CVSS 7.8 · High
Confidence
Confirmed
Exploit status
Trusted Third Party Report
EPSS
4.3%
First observed
—
Last observed
—

Decision summary

What security teams need to know first

Direct answers before the deeper technical record.

What it is

Improper privilege management in Windows Remote Desktop allows an authorized attacker to elevate privileges locally.

Have exploitation attempts been observed?

Yes. Exploitation attempts have been reported for this vulnerability. Previdian lists it as a known exploited vulnerability. Listed in CISA KEV. Also reported by third-party sources. Confidence is confirmed.

Who is affected?

Affected products include Microsoft / Windows 10 Version 1607 and 22 other products, including affected before 10.0.14393.8868, affected before 10.0.17763.8389, and affected before 10.0.19044.6937.

What should we do?

Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.

Overview

Improper privilege management in Windows Remote Desktop allows an authorized attacker to elevate privileges locally

Improper privilege management in Windows Remote Desktop allows an authorized attacker to elevate privileges locally.

Microsoft Affected
Windows 10 Version 1607
Before 10.0.14393.8868
Microsoft Affected
Windows 10 Version 1809
Before 10.0.17763.8389
Microsoft Affected
Windows 10 Version 21H2
Before 10.0.19044.6937
Microsoft Affected
Windows 10 Version 22H2
Before 10.0.19045.6937
Microsoft Affected
Windows 11 version 22H3
Before 10.0.22631.6649
Microsoft Affected
Windows 11 Version 23H2
Before 10.0.22631.6649
Microsoft Affected
Windows 11 Version 24H2
Before 10.0.26100.7840
Microsoft Affected
Windows 11 Version 25H2
Before 10.0.26200.7840
Microsoft Affected
Windows 11 version 26H1
Before 10.0.28000.1575
Microsoft Affected
Windows 11 Version 26H1
Before 10.0.28000.1575
Microsoft Affected
Windows Server 2012
Before 6.2.9200.25923
Microsoft Affected
Windows Server 2012 (Server Core installation)
Before 6.2.9200.25923
Microsoft Affected
Windows Server 2012 R2
Before 6.3.9600.23022
Microsoft Affected
Windows Server 2012 R2 (Server Core installation)
Before 6.3.9600.23022
Microsoft Affected
Windows Server 2016
Before 10.0.14393.8868
Microsoft Affected
Windows Server 2016 (Server Core installation)
Before 10.0.14393.8868
Microsoft Affected
Windows Server 2019
Before 10.0.17763.8389
Microsoft Affected
Windows Server 2019 (Server Core installation)
Before 10.0.17763.8389
Microsoft Affected
Windows Server 2022
Before 10.0.20348.4773
Microsoft Affected
Windows Server 2022, 23H2 Edition (Server Core installation)
Before 10.0.25398.2149
Microsoft Affected
Windows Server 2025
Before 10.0.26100.32370
Microsoft Affected
Windows Server 2025 (Server Core installation)
Before 10.0.26100.32370
View vendor advisory (opens in new tab)
Published
10 Feb 2026
Exploitation Attempts Reported
01 Jun 2026
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None

Tags

cisa windows microsoft

CVE References

Exploitation evidence

Evidence of exploitation attempts

Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.

Exploitation Attempts Observed in the Wild

CVE

Recorded 01 Jun 2026

A trusted third party reported exploitation attempts.

Known exploited vulnerability sources

Per-source evidence links for KEV attestations are available through the Previdian Pro API.

Learn about Pro API access
Source Added
CVE First 2026-06-01 10:50 UTC
CISA 2026-06-02 14:03 UTC

Detection

Operational artifacts and observed signals

Make the evidence actionable in scanner, SOC, and edge-control workflows.

Scanner coverage

No scanner integrations recorded yet.

Virtual patch status

No Previdian virtual patch is currently available. Future rules ship for ModSecurity, Cloudflare, and AWS WAF.

Learn about virtual patches →

No detection artifacts or sensor request patterns are available for this CVE yet.

Check back as sensor telemetry and scanner integrations are updated.

Risk and context

Severity, weaknesses, and research context

CVSS v3.1

7.8 High

Potential damage if exploited. Separate from whether attackers are using it.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C

EPSS

4.3%

Estimated chance of exploitation in the next 30 days. Previdian's warning comes from evidence, not this score.

Weaknesses

Improper Privilege Management CWE-269

Timeline

From disclosure to observed exploitation attempts

  1. 14:03 UTC

    Added to CISA KEV

    Listed in the CISA Known Exploited Vulnerabilities catalog

  2. 10:50 UTC

    Added to Previdian KEV Feed

    High-confidence, third-party report of exploitation attempts

  3. 17:51 UTC

    CVE published

    Vulnerability disclosed publicly

  4. 18:10 UTC

    CVE ID reserved

    Identifier reserved by the CNA

Pro API

Automate this intelligence

Confidence, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.

Start 14-day Pro trial Read API docs
  • Evidence confidence and provenance
  • First-party sensor telemetry
  • PoC and scanner references
  • Affected versions and enrichment
  • Automation-ready JSON delivery

GET /api/v2/pro/kevs/CVE-2026-21533

Sample API response 
{
  "cve_id": "CVE-2026-21533",
  "confidence": "Confirmed",
  "cvss_score": 7.8,
  "cvss_estimated": false,
  "epss_score": 0.04335,
  "exploit_status": {
    "exploited_in_the_wild": true,
    "active_exploitation_observed": false
  },
  "sensor_telemetry": { "attempts": 0, "sensors": 0 }
}