CVE-2021-33771
HIGHCVSS 7.8/10Actively ExploitedEPSS 6.25%
Last modified
CVE-2021-33771 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. Windows Kernel Elevation of Privilege Vulnerability. CISA has confirmed active exploitation in the wild. EPSS estimates a 6.25% chance of exploitation in the next 30 days.
Description
Windows Kernel Elevation of Privilege Vulnerability
Metrics
Exploitation Status
This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by .
Affected Software
| Vendor | Product | Versions | Update |
|---|---|---|---|
| Microsoft | Windows 10 1507 | < 10.0.10240.19003 | — |
| Microsoft | Windows 10 1607 | < 10.0.14393.4530 | — |
| Microsoft | Windows 10 1809 | < 10.0.17763.2061 | — |
| Microsoft | Windows 10 1909 | < 10.0.18363.1679 | — |
| Microsoft | Windows 10 2004 | < 10.0.19041.1110 | — |
| Microsoft | Windows 10 20h2 | < 10.0.19042.1110 | — |
| Microsoft | Windows 10 21h1 | < 10.0.19043.1110 | — |
| Microsoft | Windows 8.1 | All versions | — |
| Microsoft | Windows Rt 8.1 | All versions | — |
| Microsoft | Windows Server 2004 | < 10.0.19041.1110 | — |
| Microsoft | Windows Server 2012 | All versions | R2 |
| Microsoft | Windows Server 2016 | < 10.0.14393.4530 | — |
| Microsoft | Windows Server 2019 | < 10.0.17763.2061 | — |
| Microsoft | Windows Server 20h2 | < 10.0.19042.1110 | — |
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-33771Patch, Vendor Advisory
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-33771Patch, Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-33771US Government Resource
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
What is CVE-2021-33771?
Windows Kernel Elevation of Privilege Vulnerability
How severe is CVE-2021-33771?
CVE-2021-33771 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 6.25% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.
How do I fix CVE-2021-33771?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
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Are you affected by CVE-2021-33771?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST