CVE-2021-39252

Out-of-bounds read via crafted NTFS image

Published Sep 7, 2021 · Updated Dec 2, 2025

Out-of-bounds read in ntfs_ie_lookup in NTFS-3G before 2021.8.22 allows local users to access memory via a crafted NTFS image. The function insufficiently validates NTFS index-entry metadata before reading it, so malformed image data drives a read beyond the intended buffer. Reachability requires local access to process the image or physical access to attach storage to a system configured to invoke NTFS-3G tools; the individual flaw's ultimate consequence beyond the invalid read is not publicly isolated from the advisory's broader vulnerability set.

CVSS severity7.8
High
EPSS probability0.43%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in ntfs_ie_lookup in NTFS-3G before 2021.8.22 allows local users to access memory via a crafted NTFS image. The function insufficiently validates NTFS index-entry metadata before reading it, so malformed image data drives a read beyond the intended buffer. Reachability requires local access to process the image or physical access to attach storage to a system configured to invoke NTFS-3G tools; the individual flaw's ultimate consequence beyond the invalid read is not publicly isolated from the advisory's broader vulnerability set.

The record

CVE
CVE-2021-39252
Published
Sep 7, 2021
Updated
Dec 2, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-125, CWE-20, T1203
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 7, 2021CVE publishedPublication date reported by the CVE source.
  2. Dec 2, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.7CISA-ADPCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
6.9NIST NVDAV:L/AC:M/Au:N/C:C/I:C/A:C
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
CWE-20Improper Input Validation
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

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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