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Debian LinuxOperating system · Debian

CVE-2021-33287

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
In NTFS-3G versions < 2021.8.22, when specially crafted NTFS attributes are read in the function ntfs_attr_pread_i, a heap buffer overflow can occur and allow for writing to arbitrary memory or denial of service of the application.

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

A heap buffer overflow vulnerability exists in NTFS-3G versions prior to 2021.8.22 within the ntfs_attr_pread_i function. The vulnerability is triggered when specially crafted NTFS attributes are read, potentially allowing an attacker to write to arbitrary memory locations or cause a denial of service.

MitigationUpgrade to NTFS-3G version 2021.8.22 or later to obtain the patch that adds proper bounds checking in the ntfs_attr_pread_i function to prevent heap buffer overflows when reading NTFS attributes.

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 NTFS-3G package version
    Run 'ntfs-3g --version' or check your package manager (dpkg -l ntfs-3g, rpm -q ntfs-3g, etc.)
    Affected if Version is lower than 2021.8.22 or the version cannot be determined (indicating an older unpatched build)
  2. Identify NTFS-3G binary location
    Run 'which ntfs-3g' or 'type ntfs-3g' to locate the binary
    Affected if The ntfs-3g binary exists and is executable, enabling the vulnerable code path
  3. Confirm NTFS mounting capability
    Check if the system can mount NTFS filesystems using 'mount -t ntfs-3g' or check /sbin/mount.ntfs
    Affected if NTFS-3G is installed and configured for mounting, meaning the vulnerable ntfs_attr_pread_i function can be invoked when reading malformed NTFS attributes

You are affected if NTFS-3G with version lower than 2021.8.22 is installed and usable for mounting NTFS filesystems, as the heap buffer overflow in ntfs_attr_pread_i triggers when reading specially crafted NTFS attributes.

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 to NTFS-3G version 2021.8.22 or later to obtain the patch that adds proper bounds checking in the ntfs_attr_pread_i function to prevent heap buffer overflows when reading NTFS attributes.

Recommended fix High confidence

NTFS-3G version 2021.8.22 or later

  1. Update your system's package repository metadata: run 'apt update' (Debian/Ubuntu), 'dnf check-update' (Fedora), or 'emerge --sync' (Gentoo)
  2. Upgrade NTFS-3G package: run 'apt install ntfs-3g' (Debian/Ubuntu), 'dnf update ntfs-3g' (Fedora), or 'emerge --ask ntfs-3g' (Gentoo)
  3. Verify the installed version is 2021.8.22 or later by running 'ntfs-3g --version'
  4. If your distribution does not have 2021.8.22 yet, consider building from source: download from https://github.com/tuxera/ntfs-3g/releases/tag/2021.8.22 or later, then run './configure && make && make install'
Caveat Minor behavior changes possible; verify NTFS mount functionality after upgrade

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

Fix this in Debian Linux Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA2.0 h
22.0 hours of engineering $3,800
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,080.

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-2021-33287 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