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Enterprise Linux DesktopOperating system · Redhat

CVE-2018-12379

HIGH · 7.8 CVSS v3.0 Published 2018-10-18
Fix available
A fix is available. Upgrade to 60.2.0 / 62.0 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
When the Mozilla Updater opens a MAR format file which contains a very long item filename, an out-of-bounds write can be triggered, leading to a potentially exploitable crash. This requires running the Mozilla Updater manually on the local system with the malicious MAR file in order to occur. This vulnerability affects Firefox < 62, Firefox ESR < 60.2, and Thunderbird < 60.2.1.

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

Mozilla Updater contains an out-of-bounds write vulnerability when processing MAR (Mozilla Archive) files containing excessively long item filenames. A malicious MAR file can trigger memory corruption leading to potential code execution. The attack requires the user to manually run the updater with the malicious file, making it a local privilege escalation scenario.

MitigationUpdate to Firefox 62+, Firefox ESR 60.2+, or Thunderbird 60.2.1+. Until patched, avoid running the Mozilla Updater with untrusted or locally-provided MAR files.

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
Enterprise Linux DesktopOperating system
Affected:= 6.0= 7.0
Enterprise Linux ServerOperating system
Affected:= 6.0= 7.0
Enterprise Linux Server AusOperating system
Affected:= 7.6
Enterprise Linux Server EusOperating system
Affected:= 7.5= 7.6
Enterprise Linux Server TusOperating system
Affected:= 7.6
Enterprise Linux WorkstationOperating system
Affected:= 6.0= 7.0
Debian LinuxOperating system
Affected:= 8.0= 9.0
FirefoxWeb browser
Affected:< 60.2.0< 62.0

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:3.0/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. Locate the Mozilla Updater binary
    Search for updater or updater.exe in typical Mozilla installation directories (e.g., /usr/lib/firefox/, /usr/lib64/firefox/, C:\Program Files\Mozilla Firefox\), or use: find / -name 'updater' -type f 2>/dev/null on Linux, Get-ChildItem -Recurse -Filter updater.exe on Windows
    Affected if The Mozilla Updater binary exists on the system and its version is below the fixed releases (Firefox 62+, Firefox ESR 60.2+, Thunderbird 60.2.1+)
  2. Determine installed Firefox version
    Run: firefox --version (Linux) or check the about dialog in Firefox (Windows/Mac), or inspect the version file in the installation directory such as /usr/lib/firefox/greprefs/version.js or application.ini
    Affected if Firefox version is less than 60.2.0 or less than 62.0 (depending on the release channel)
  3. Check operating system version for Red Hat Enterprise Linux
    Run: cat /etc/redhat-release or hostnamectl | grep "Red Hat"
    Affected if The system is RHEL 6.0, 7.0, 7.5, 7.6, or derivative (Server, Desktop, Workstation, Aus, Eus, Tus variants) and contains the vulnerable Mozilla Updater component
  4. Check operating system version for Debian Linux
    Run: cat /etc/debian_version or lsb_release -a
    Affected if The system is Debian Linux 8.0 (Jessie) or 9.0 (Stretch) and contains the vulnerable Mozilla Updater component
  5. Verify if custom MAR file processing is accessible
    Inspect file permissions and directory access for the updater binary and MAR file locations (typically /var/lib/updater/ or user-accessible directories). Check if the updater can be invoked from command line with a user-supplied MAR file.
    Affected if A local user can invoke the Mozilla Updater with a manually crafted MAR file, enabling exploitation of the out-of-bounds write

The environment is affected if the Mozilla Updater is present with a version bundled in Firefox below 60.2.0/62.0, or if running on a vulnerable RHEL/Debian version, and the attacker can supply a malicious MAR file to the updater.

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
Upgrade available Upgrade to 60.2.0 / 62.0 or later
Fixed in 60.2.062.0
Interim mitigation

Update to Firefox 62+, Firefox ESR 60.2+, or Thunderbird 60.2.1+. Until patched, avoid running the Mozilla Updater with untrusted or locally-provided MAR files.

Fix this in Enterprise Linux Desktop Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing1.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,450
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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-2018-12379 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