CVE-2021-33285

Memory disclosure or DoS via malformed MFT metadata

Published Sep 7, 2021 · Updated Dec 3, 2025

Heap buffer overflow in NTFS-3G before 2021.8.22 allows local users to disclose process memory or interrupt processing via a crafted NTFS volume. ntfs_get_attribute_value continues parsing an MFT record when bytes_in_use exceeds bytes_allocated, causing out-of-bounds heap access. Exploitation requires mounting attacker-controlled media or an image through NTFS-3G; the public record does not identify the interruption as a hang or crash.

CVSS severity7.8
High
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in NTFS-3G before 2021.8.22 allows local users to disclose process memory or interrupt processing via a crafted NTFS volume. ntfs_get_attribute_value continues parsing an MFT record when bytes_in_use exceeds bytes_allocated, causing out-of-bounds heap access. Exploitation requires mounting attacker-controlled media or an image through NTFS-3G; the public record does not identify the interruption as a hang or crash.

The record

CVE
CVE-2021-33285
Published
Sep 7, 2021
Updated
Dec 3, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, CWE-20
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 7, 2021CVE publishedPublication date reported by the CVE source.
  2. Dec 3, 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
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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
CWE-20Improper Input Validation

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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