Debian LinuxOperating system · Debian
CVE-2021-39258
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 · uneditedA crafted NTFS image can cause out-of-bounds reads in ntfs_attr_find and ntfs_external_attr_find in NTFS-3G < 2021.8.22.
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 confidenceNTFS-3G versions prior to 2021.8.22 contain out-of-bounds read vulnerabilities in the ntfs_attr_find and ntfs_external_attr_find functions. When mounting a specially crafted NTFS image, these functions can read memory outside allocated buffer bounds, potentially exposing sensitive information or causing application crashes.
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
= 9.0= 10.0= 11.0< 2021.8.22CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Check if NTFS-3G is installedRun 'dpkg -l | grep ntfs-3g' on Debian-based systems, or 'rpm -qa | grep ntfs-3g' on RHEL-based systems, or check for the binary at /sbin/mount.ntfs or /usr/bin/ntfs-3gAffected if The package or binary is present on the system
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Determine the installed NTFS-3G versionRun 'ntfs-3g --version' or 'dpkg -l ntfs-3g' to get the exact version numberAffected if The version shown is earlier than 2021.8.22 or the command fails to return a version
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Check if NTFS mounting is configured or usedReview /etc/fstab for NTFS entries, check /proc/mounts for currently mounted NTFS filesystems, or look for ntfs-3g in system mount configurationsAffected if NTFS volumes are mounted or configured to be mounted using NTFS-3G
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Identify the NTFS-3G package sourceRun 'apt-cache policy ntfs-3g' on Debian systems to see the available version from repositories, or check the package origin metadataAffected if The installed version comes from an unpatched repository (Debian 9, 10, or 11 main repos pre-fix)
A system is affected if NTFS-3G is installed with a version earlier than 2021.8.22 and the system mounts or may mount NTFS images.
Generated from the published advisory. Verify against your own configuration.
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 · scoped2021.8.22
Upgrade NTFS-3G to version 2021.8.22 or later. Avoid mounting untrusted NTFS images from unknown sources until the upgrade is applied.
NTFS-3G version 2021.8.22 or later
- Update your system's package list: 'apt-get update' (Debian) or 'emerge --sync' (Gentoo)
- Upgrade NTFS-3G to version 2021.8.22 or later: 'apt-get install ntfs-3g' (Debian) or 'emerge --ask sys-fs/ntfs3g' (Gentoo)
- Verify the installed version matches or exceeds 2021.8.22 using 'ntfs-3g --version'
- Reboot or remount any NTFS filesystems if they were previously mounted to ensure the updated library is in use
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Debian Linux
Scoped from the published advisory
- Consultation1.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,376.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-39258 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-39258 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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