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Debian LinuxOperating system · Debian

CVE-2017-14121

MEDIUM · 5.5 CVSS v3.1 Published 2017-09-03
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
58/100
Remediation priority · Elevated
No privileges

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
The DecodeNumber function in unrarlib.c in unrar 0.0.1 (aka unrar-free or unrar-gpl) suffers from a NULL pointer dereference flaw triggered by a crafted RAR archive. NOTE: this may be the same as one of the several test cases in the CVE-2017-11189 references.

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 NULL pointer dereference vulnerability exists in the DecodeNumber function in unrarlib.c of unrar 0.0.1 (unrar-free/unrar-gpl). When processing a specially crafted RAR archive, the function attempts to dereference a NULL pointer, causing a denial of service (crash) or potentially other undefined behavior.

MitigationAvoid processing untrusted or unknown RAR archives with vulnerable versions. If possible, upgrade to a maintained version of unrar or use alternative RAR extraction libraries that receive security updates.

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
UnrarApplication
Affected:= 0.0.1

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
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/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 unrar is installed
    Run 'dpkg -l | grep -i unrar' on Debian-based systems, or 'rpm -qa | grep -i unrar' on RHEL-based systems, or 'which unrar' to locate the binary
    Affected if unrar package or binary is present on the system
  2. Identify the installed unrar version
    Run 'unrar' with no arguments or 'unrar -v' to display version information, or use 'dpkg -s unrar' (Debian) or 'rpm -qi unrar' (RHEL) to query package details
    Affected if version reported is 0.0.1 or the package is from Debian Linux 9.0
  3. Verify the binary file information
    Run 'file $(which unrar)' or check the binary metadata to confirm it is unrar-free, unrar-gpl, or an unrar 0.0.1 variant
    Affected if binary identifies as unrar 0.0.1, unrar-free, or unrar-gpl version 0.0.1
  4. Determine if the system processes RAR archives
    Review system logs, search for .rar file access, or check if users commonly extract RAR archives using unrar
    Affected if users or automated processes use this unrar version to extract RAR archives

A system is affected if unrar version 0.0.1 (or the Debian 9.0 packaged version) is installed and actively used to process RAR archive files.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Avoid processing untrusted or unknown RAR archives with vulnerable versions. If possible, upgrade to a maintained version of unrar or use alternative RAR extraction libraries that receive security updates.

Fix this in Debian Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
7.0 hours of engineering $1,240
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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-2017-14121 in production — separate from our analysis above.

No notes yet

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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