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CVE Record

CVE-2021-39260: A crafted NTFS image can cause an out-of-bounds access in ntfs_inode_sync_standard_information in NTFS-3G <...

A crafted NTFS image can cause an out-of-bounds access in ntfs_inode_sync_standard_information 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-2021-39260 affects NTFS-3G before 2021.8.22. A specially crafted NTFS image can trigger out-of-bounds memory access. Business risk is mainly where servers, forensic workstations, or automation handle untrusted NTFS media or images with elevated privileges.

Executive priority

Treat as a targeted hygiene fix rather than an emergency. Prioritize endpoints, forensic systems, support tooling, and servers that process untrusted NTFS media. Patch through normal vulnerability management unless such workflows are exposed or high-value.

Technical view

The issue is a CWE-20 input validation flaw in ntfs_inode_sync_standard_information. The CVSS 3.1 vector is local, low complexity, high privileges required, and high confidentiality, integrity, and availability impact. The source bundle identifies NTFS-3G versions before 2021.8.22 as affected.

Likely exposure

Exposure is most likely on Linux or Unix systems with NTFS-3G installed, especially workflows that mount or process NTFS disks, removable media, or forensic images. The provided affected-product metadata is incomplete, so validate against installed package versions and distro advisories.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation. The CVSS vector requires local access and high privileges, which reduces broad internet-scale risk, but untrusted image handling can still create a meaningful operational exposure.

Researcher notes

Evidence supports an out-of-bounds access in NTFS-3G before 2021.8.22, but the bundle does not include exploit details, active exploitation evidence, or comprehensive downstream package versions. Validate fixes through vendor package metadata, not only upstream version strings.

Mitigation direction

  • Upgrade NTFS-3G to 2021.8.22 or later where available.
  • Apply fixed Debian, Gentoo, or other vendor-maintained packages.
  • Check vendor advisories for exact fixed package versions.
  • Avoid processing untrusted NTFS images on production systems.
  • Use isolated analysis hosts for removable media and disk images.

Validation and detection

  • Inventory systems with NTFS-3G installed.
  • Confirm each installed version is 2021.8.22 or later.
  • Check package status against Debian, Gentoo, or relevant distro advisories.
  • Identify workflows that mount untrusted NTFS media or images.
  • Verify those workflows run in isolated, least-privilege environments.
Prepared
Confidence
high
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

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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-2021-39260 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-2021-39260Attack 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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