CVE-2021-28312Public exploit

Service interruption via crafted NTFS stream path

Published Apr 13, 2021 · Updated Oct 1, 2024

Denial of service in Microsoft Windows NTFS allows attackers to interrupt an affected system by accessing a crafted directory path. NTFS mishandles a directory-index metadata stream path ending in :$i30:$bitmap, marks the volume dirty, and schedules CHKDSK for the next reboot. The action requires victim interaction under Microsoft's local assessment; the immediate effect is a filesystem warning and reboot-time disk checking, although public testing also produced an unbootable system.

CVSS severity3.3
Low
EPSS probability6.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Microsoft Windows NTFS allows attackers to interrupt an affected system by accessing a crafted directory path. NTFS mishandles a directory-index metadata stream path ending in :$i30:$bitmap, marks the volume dirty, and schedules CHKDSK for the next reboot. The action requires victim interaction under Microsoft's local assessment; the immediate effect is a filesystem warning and reboot-time disk checking, although public testing also produced an unbootable system.

The record

CVE
CVE-2021-28312
Published
Apr 13, 2021
Updated
Oct 1, 2024
Vendor
Microsoft
Product
Windows Server 2019
Classifications
T1499
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Oct 1, 2024Record 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.

  1. Affected versionversion=10.0.0 <publication

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Microsoft · Windows Server 2019version=10.0.0 <publication
Microsoft · Windows 10 Version 1909version=10.0.0 <publication
Microsoft · Windows Server, version 2004version=10.0.0 <publication
Microsoft · Windows 10 Version 20H2version=10.0.0 <publication
Microsoft · Windows Server 2019 (Server Core installation)version=10.0.0 <publication
Microsoft · Windows Server version 20H2version=10.0.0 <publication
Microsoft · Windows 10 Version 2004version=10.0.0 <publication
Microsoft · Windows 10 Version 1809version=10.0.0 <publication
Microsoft · Windows Server, version 1909 (Server Core installation)version=10.0.0 <publication

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:N/A:P
3.3Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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