Security readout for executives and security teams
Plain-English summary
CVE-2021-39254 affects NTFS-3G before 2021.8.22. A malicious NTFS disk image can trigger memory corruption while NTFS-3G resizes an attribute record. Business urgency is moderate because exploitation is local and requires high privileges, but successful abuse could affect confidentiality, integrity, and availability.
Executive priority
Treat as a moderate patching item. Prioritize systems that handle removable media, disk images, or forensic evidence, especially where privileged automation processes NTFS content.
Technical view
The flaw is an integer overflow leading to a heap-based buffer overflow in ntfs_attr_record_resize, reached through a crafted NTFS image. The CVSS 3.1 vector is AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H, indicating local, low-complexity exploitation requiring high privileges and no user interaction.
Likely exposure
Exposure is most likely on Linux or Unix-like systems that include NTFS-3G before 2021.8.22 or distribution packages covered by Debian, Fedora, or Gentoo advisories. The source bundle does not provide precise affected CPEs.
Exploitation context
The bundle does not cite active exploitation, and KEV is false. Practical risk depends on whether privileged local users or services process untrusted NTFS images. No remote exploitation path is described in the provided sources.
Researcher notes
The affected product metadata is incomplete in the bundle, but the description and advisories identify NTFS-3G before 2021.8.22. The key technical issue is integer overflow before memmove, producing heap corruption in ntfs_attr_record_resize.
Mitigation direction
- Upgrade NTFS-3G to 2021.8.22 or later where available.
- Apply fixed distribution packages from Debian, Fedora, Gentoo, or your OS vendor.
- Limit privileged processing or mounting of untrusted NTFS images.
- Check vendor guidance if running backported distribution packages.
Validation and detection
- Inventory installed ntfs-3g package versions across Linux and Unix-like hosts.
- Confirm versions are 2021.8.22 or vendor-fixed backports.
- Review systems that mount or inspect removable or user-supplied NTFS media.
- Verify package updates are deployed on servers, endpoints, and forensic workstations.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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-190: Exact CWE lookup
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Open ATT&CK lookupCWE-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.
Open ATT&CK lookupCVE-2021-39254 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- 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
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.
CVSS vector scores
1 official scoreWe 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.
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H0.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.7MediumVector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/tuxera/ntfs-3g/releasesCVE reference
- https://github.com/tuxera/ntfs-3g/security/advisories/GHSA-q759-8j5v-q5jpCVE reference
- DSA-4971CVE reference · vendor-advisory
- FEDORA-2021-e7c8ba6301CVE reference · vendor-advisory
- FEDORA-2021-5b1dac797bCVE reference · vendor-advisory
- [debian-lts-announce] 20211116 [SECURITY] [DLA 2819-1] ntfs-3g security updateCVE reference · mailing-list
- GLSA-202301-01CVE reference · vendor-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Integer Overflow or Wraparound
Integer Overflow or Wraparound represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Improper Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.