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Debian LinuxOperating system · Debian

CVE-2021-35269

HIGH · 7.8 CVSS v3.1 Published 2021-09-07
Fix available
A fix is available. Upgrade to 2021.8.22 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
NTFS-3G versions < 2021.8.22, when a specially crafted NTFS attribute from the MFT is setup in the function ntfs_attr_setup_flag, a heap buffer overflow can occur allowing for code execution and escalation of privileges.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Heap buffer overflow vulnerability in NTFS-3G's ntfs_attr_setup_flag function when parsing specially crafted NTFS attributes from the Master File Table (MFT). Successful exploitation allows code execution with elevated privileges.

MitigationUpgrade NTFS-3G to version 2021.8.22 or later to obtain the patched version that addresses the heap overflow in MFT attribute parsing.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Debian LinuxOperating system
Affected:= 9.0= 10.0= 11.0
FedoraOperating system
Affected:= 33= 35
Ntfs 3gApplication
Affected:< 2021.8.22

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if NTFS-3G is installed
    Run 'dpkg -l | grep ntfs-3g' on Debian/Ubuntu or 'rpm -qa | grep ntfs-3g' on Fedora/RHEL
    Affected if Package is not installed means not affected in this context
  2. Determine installed NTFS-3G version
    Run 'ntfs-3g --version' or 'dpkg -s ntfs-3g | grep Version' on Debian, or 'rpm -q ntfs-3g' on Fedora
    Affected if Version is less than 2021.8.22, or matches Debian 9.0/10.0/11.0 or Fedora 33/35 package versions
  3. Verify NTFS mounting capability is available
    Check for ntfs-3g binary at /usr/bin/ntfs-3g or run 'which ntfs-3g'; also check /proc/filesystems for ntfs support
    Affected if ntfs-3g binary exists and NTFS support is present means the vulnerable parsing code can be triggered when mounting NTFS volumes
  4. Check for recent MFT attribute parsing activity (optional)
    Review system logs for NTFS mount operations using ntfs-3g: 'dmesg | grep -i ntfs' or check /var/log/syslog for ntfs-3g mount events
    Affected if NTFS volumes have been mounted using ntfs-3g indicates potential exposure to the vulnerable MFT attribute parsing code

You are affected if NTFS-3G version is installed and is less than 2021.8.22, and NTFS volumes can be mounted using the ntfs-3g driver.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2021.8.22 or later
Fixed in 2021.8.22
Interim mitigation

Upgrade NTFS-3G to version 2021.8.22 or later to obtain the patched version that addresses the heap overflow in MFT attribute parsing.

Recommended fix High confidence

NTFS-3G version 2021.8.22 or later

  1. Update your system's package cache (apt-get update for Debian/Ubuntu, dnf check-update for Fedora)
  2. Upgrade the ntfs-3g package to version 2021.8.22 or later using your package manager (apt-get install ntfs-3g or dnf update ntfs-3g)
  3. Reboot the system or remount any NTFS filesystems to ensure the updated library is loaded
  4. Verify the installed version using: ntfs-3g --version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Debian Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,224.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-35269 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data