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
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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.
Related CVEs from 2021
- CVE-2021-33764Windows Key Distribution Center Information Disclosure Vulne…5.9
- CVE-2021-33765Windows Installer Spoofing Vulnerability6.2
- CVE-2021-33766Microsoft Exchange Server Information Disclosure Vulnerabili…7.3
- CVE-2021-33767Open Enclave SDK Elevation of Privilege Vulnerability8.2
- CVE-2021-33768Microsoft Exchange Server Elevation of Privilege Vulnerabili…8
- CVE-2021-3377The npm package ansi_up converts ANSI escape codes into HTML…6.1
- CVE-2021-33772Windows TCP/IP Driver Denial of Service Vulnerability7.5
- CVE-2021-33773Windows Remote Access Connection Manager Elevation of Privil…7.8
- CVE-2021-33774Windows Event Tracing Elevation of Privilege Vulnerability7
- CVE-2021-33775HEVC Video Extensions Remote Code Execution Vulnerability7.8
- CVE-2021-33776HEVC Video Extensions Remote Code Execution Vulnerability7.8
- CVE-2021-33777HEVC Video Extensions Remote Code Execution Vulnerability7.8
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