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CVE Record

CVE-2021-39262: A crafted NTFS image can cause an out-of-bounds access in ntfs_decompress in NTFS-3G < 2021.8.22.

A crafted NTFS image can cause an out-of-bounds access in ntfs_decompress in NTFS-3G < 2021.8.22.

MediumCVSS 6.7Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-39262 affects NTFS-3G before 2021.8.22. A specially crafted NTFS image can trigger out-of-bounds access during decompression. The business risk is concentrated where systems mount or process untrusted NTFS media or images, especially with elevated privileges.

Executive priority

Treat this as moderate priority. Patch during the normal vulnerability cycle, but accelerate remediation for systems that process untrusted storage media or disk images, because impact can be severe if the vulnerable path is reachable.

Technical view

The issue is an input-validation flaw in ntfs_decompress, tracked as CWE-20. The CVSS 3.1 vector is local, low complexity, high privileges, no user interaction, with high confidentiality, integrity, and availability impact. Sources identify affected NTFS-3G versions before 2021.8.22.

Likely exposure

Likely exposed assets include Linux systems, forensic workstations, file-ingestion pipelines, or appliances using vulnerable NTFS-3G to mount NTFS disks, removable media, or image files. Exposure is lower for systems that never process untrusted NTFS content.

Exploitation context

The bundle does not show active exploitation, and CISA KEV status is false. The vulnerability requires local attack conditions with high privileges according to the CVSS vector, but crafted NTFS content may matter in workflows that automatically mount or inspect supplied images.

Researcher notes

The provided metadata lacks detailed affected CPEs and downstream fixed package versions. Analysis should focus on NTFS-3G before 2021.8.22 and distribution advisories. Avoid assuming remote reachability or exploitation without additional evidence.

Mitigation direction

  • Update NTFS-3G to 2021.8.22 or later where upstream packages are used.
  • Apply Debian, Debian LTS, Gentoo, or other distribution security updates.
  • Restrict mounting or processing of untrusted NTFS images until patched.
  • Review automated media-ingestion and forensic pipelines for vulnerable NTFS-3G use.

Validation and detection

  • Inventory systems with NTFS-3G installed and record package versions.
  • Confirm installed versions are not earlier than 2021.8.22 or are distro-fixed builds.
  • Check whether workflows mount untrusted NTFS disks, USB media, or image files.
  • Verify security advisories from the relevant operating-system vendor were applied.
Prepared
Confidence
medium
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-20: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2021-39262 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
6.7 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
6Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
6.7CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H0.85.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

6.7Medium
CVSS 3.1 vector shape for CVE-2021-39262Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

CWE-20

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-20 · source CWE mapping

Improper Input Validation

Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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