CVE-2021-33771
Confirmed PUBLISHEDWindows Kernel Elevation of Privilege Vulnerability
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
Windows Kernel Elevation of Privilege Vulnerability
- CVE Published
- Jul 14, 2021
- Exploitation Reported
- Nov 03, 2021
- CVSS
- 7.8 High
- EPSS
- —
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| Microsoft |
Windows 10 Version 1809
|
10.0.0 to < 10.0.17763.2061 |
Affected |
| Microsoft |
Windows Server 2019
|
10.0.0 to < 10.0.17763.2061 |
Affected |
| Microsoft |
Windows Server 2019 (Server Core installation)
|
10.0.0 to < 10.0.17763.2061 |
Affected |
| Microsoft |
Windows 10 Version 1909
|
10.0.0 to < 10.0.18363.1679 |
Affected |
| Microsoft |
Windows 10 Version 21H1
|
10.0.0 to < 10.0.19043.1110 |
Affected |
| Microsoft |
Windows 10 Version 2004
|
10.0.0 to < 10.0.19041.1110 |
Affected |
| Microsoft |
Windows Server version 2004
|
10.0.0 to < 10.0.19041.1110 |
Affected |
| Microsoft |
Windows 10 Version 20H2
|
10.0.0 to < 10.0.19042.1110 |
Affected |
| Microsoft |
Windows Server version 20H2
|
10.0.0 to < 10.0.19042.1110 |
Affected |
| Microsoft |
Windows 10 Version 1507
|
10.0.0 to < 10.0.10240.19003 |
Affected |
| Microsoft |
Windows 10 Version 1607
|
10.0.0 to < 10.0.14393.4530 |
Affected |
| Microsoft |
Windows Server 2016
|
10.0.0 to < 10.0.14393.4530 |
Affected |
| Microsoft |
Windows Server 2016 (Server Core installation)
|
10.0.0 to < 10.0.14393.4530 |
Affected |
| Microsoft |
Windows 8.1
|
6.3.0 to < 6.3.9600.20069 |
Affected |
| Microsoft |
Windows Server 2012 R2
|
6.3.0 to < 6.3.9600.20069 |
Affected |
| Microsoft |
Windows Server 2012 R2 (Server Core installation)
|
6.3.0 to < 6.3.9600.20069 |
Affected |
CVE References
- portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33771 portal.msrc.microsoft.com · CVE Record https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CV...
Recommended Actions
- Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CISA First | 2021-11-03 00:00 UTC |
No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
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
Exploitation Status
Exploited in the wild
Recorded 2021-11-03 00:00:00 UTC · CISA
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
00:00 UTC over 4 years ago00:00 UTC · over 4 years ago
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
17:53 UTC about 5 years ago17:53 UTC · about 5 years ago
CVE published
Vulnerability disclosed publicly
-
00:00 UTC about 5 years ago00:00 UTC · about 5 years ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2021-33771
{
"cve_id": "CVE-2021-33771",
"title": "Windows Kernel Elevation of Privilege Vulnerability",
"affected_vendor": "Microsoft",
"affected_product": "Windows 10 Version 1809, Windows Server 2019, Windows Server 2019 (Server Core installation), Windows 10 Version 1909, Windows 10 Version 21H1, Windows 10 Version 2004, Windows Server version 2004, Windows 10 Version 20H2, Windows Server version 20H2, Windows 10 Version 1507, Windows 10 Version 1607, Windows Server 2016, Windows Server 2016 (Server Core installation), Windows 8.1, Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation)",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 7.8,
"epss_score": null,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}