Service interruption by low-privileged guest OS users
Published Jul 14, 2021 · Updated Aug 10, 2026
Denial of service in Microsoft Hyper-V on affected Windows 10 and Windows Server 2016 builds allows guest OS users to interrupt the host. Microsoft has not published the affected Hyper-V component, the malformed input, or the operation that mishandles it. Exploitation requires low-privileged network access; builds before 10.0.14393.4530 have an availability impact without reported data disclosure or modification.
Summary
What happened
Denial of service in Microsoft Hyper-V on affected Windows 10 and Windows Server 2016 builds allows guest OS users to interrupt the host. Microsoft has not published the affected Hyper-V component, the malformed input, or the operation that mishandles it. Exploitation requires low-privileged network access; builds before 10.0.14393.4530 have an availability impact without reported data disclosure or modification.
The record
- CVE
- CVE-2021-33758
- Published
- Jul 14, 2021
- Updated
- Aug 10, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2016 (Server Core installation)
- Classifications
- T1499.004
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 14, 2021CVE publishedPublication date reported by the CVE source.
- Aug 10, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.14393.0 <10.0.14393.4530
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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