What it is
CVE-2026-21510 is an unauthenticated Windows Shell Security Feature Bypass Vulnerability affecting Microsoft Windows 10 Version 1607 and 22 other products. Protection mechanism failure in Windows Shell allows an...
Vulnerability report
Exploited in the wild
Confirmed confidence
In CISA KEV
CVE-2026-21510
Windows Shell Security Feature Bypass Vulnerability
Microsoft / Windows 10 Version 1607 · affected before 10.0.14393.8868
- Severity
- CVSS 8.8 · High
- Confidence
- Confirmed
- Exploit status
- Exploited in the wild
- EPSS
- 25.8%
- First observed
- —
- Last observed
- —
Decision summary
What security teams need to know first
Direct answers before the deeper technical record.
Is it exploited?
Yes. KEV Intelligence tracks this CVE as a known exploited vulnerability. Confidence is confirmed.
Who is affected?
Microsoft / Windows 10 Version 1607 affected before 10.0.14393.8868.
What should we do?
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
Overview
Windows Shell Security Feature Bypass Vulnerability
Protection mechanism failure in Windows Shell allows an unauthorized attacker to bypass a security feature over a network.
Vendor
Product
Affected
Status
Microsoft
Windows 10 Version 1607
Before 10.0.14393.8868
Affected
Microsoft
Windows 10 Version 1809
Before 10.0.17763.8389
Affected
Microsoft
Windows 10 Version 21H2
Before 10.0.19044.6937
Affected
Microsoft
Windows 10 Version 22H2
Before 10.0.19045.6937
Affected
Microsoft
Windows 11 version 22H3
Before 10.0.22631.6649
Affected
Microsoft
Windows 11 Version 23H2
Before 10.0.22631.6649
Affected
Microsoft
Windows 11 Version 24H2
Before 10.0.26100.7840
Affected
Microsoft
Windows 11 Version 25H2
Before 10.0.26200.7840
Affected
Microsoft
Windows 11 version 26H1
Before 10.0.28000.1575
Affected
Microsoft
Windows 11 Version 26H1
Before 10.0.28000.1575
Affected
Microsoft
Windows Server 2012
Before 6.2.9200.25923
Affected
Microsoft
Windows Server 2012 (Server Core installation)
Before 6.2.9200.25923
Affected
Microsoft
Windows Server 2012 R2
Before 6.3.9600.23022
Affected
Microsoft
Windows Server 2012 R2 (Server Core installation)
Before 6.3.9600.23022
Affected
Microsoft
Windows Server 2016
Before 10.0.14393.8868
Affected
Microsoft
Windows Server 2016 (Server Core installation)
Before 10.0.14393.8868
Affected
Microsoft
Windows Server 2019
Before 10.0.17763.8389
Affected
Microsoft
Windows Server 2019 (Server Core installation)
Before 10.0.17763.8389
Affected
Microsoft
Windows Server 2022
Before 10.0.20348.4773
Affected
Microsoft
Windows Server 2022, 23H2 Edition (Server Core installation)
Before 10.0.25398.2149
Affected
Microsoft
Windows Server 2025
Before 10.0.26100.32370
Affected
Microsoft
Windows Server 2025 (Server Core installation)
Before 10.0.26100.32370
Affected
- Published
- 10 Feb 2026
- Exploitation Reported
- 01 Jun 2026
- Attack vector
- Remote
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
Tags
cisa
windows
microsoft
CVE References
- CVE Record CVE.org · CVE Record https://www.cve.org/CVERecord?id=CVE-2026-21510
- Windows Shell Security Feature Bypass Vulnerability msrc.microsoft.com · Vendor Advisory https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21510
Exploitation evidence
Why KEV Intelligence marks this CVE as exploited
Third-party attestation and first-party sensor observation are shown separately so teams can judge the evidence chain.
Exploited in the wild
CVE
Independent exploitation attestation added to the KEV Intelligence record.
Known exploited vulnerability sources
Per-source evidence links for KEV attestations are available through the KEV Intelligence 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.
Observed signals
- Request targets
- 0
- User-Agents
- 0
Raw values available in Pro and Enterprise.
Scanner coverage
No scanner integrations recorded yet.
Virtual patch status
No KEV Intelligence 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
8.8
High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS
25.8%
Weaknesses
Timeline
From disclosure to observed exploitation
-
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
Added to KEV Intelligence KEV Feed
High-confidence, third-party attested exploitation
-
CVE published
Vulnerability disclosed publicly
-
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.
- 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-2026-21510
Free JSON includes basic KEV fields{
"cve_id": "CVE-2026-21510",
"confidence": "Confirmed",
"cvss_score": 8.8,
"cvss_estimated": false,
"epss_score": 0.25835,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "attempts": 0, "sensors": 0 }
}Early warning alerts
Get alerts on high-impact exploitation
Receive curator-selected alerts when exploitation activity warrants attention. Each alert includes the evidence and context needed to decide what requires attention now.