Enterprise Linux DesktopOperating system · Redhat

CVE-2018-12376

CRITICAL · 9.8 CVSS v3.0 Published 2018-10-18

Mitigation only

No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.

See remediation →

100/100

Remediation priority · Urgent

Remotely reachable No privileges Zero-click

Official description

NVD · unedited

Memory safety bugs present in Firefox 61 and Firefox ESR 60.1. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This vulnerability affects Firefox < 62, Firefox ESR < 60.2, and Thunderbird < 60.2.1.

Technical summary

dbcve analysis · moderate confidence

Memory safety bugs in Firefox 61 and Firefox ESR 60.1 allow memory corruption that can be exploited to run arbitrary code. This affects the browser's rendering engine and represents classic memory corruption vulnerabilities (likely buffer overflows or use-after-free conditions) in the Firefox core.

MitigationUpgrade to Firefox 62+, Firefox ESR 60.2+, or Thunderbird 60.2.1+ to patch the memory safety vulnerabilities.

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

Affected products & versions

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

Ubuntu LinuxOperating system

Affected:= 14.04= 16.04= 18.04

CVSS breakdown

From the vector

Attack vector: Network
Complexity: Low
Privileges: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected?

dbcve checks

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

Verify Firefox is installed

Run 'which firefox' or check for Firefox in your application menu/file system. On Red Hat systems, also check 'rpm -qa | grep firefox'. On Debian/Ubuntu, check 'dpkg -l | grep firefox' or 'apt list --installed 2>/dev/null | grep firefox'.

Affected if Firefox is not found on the system, then this CVE does not apply.
Determine installed Firefox version

Run 'firefox --version' in a terminal. If that fails, open Firefox and navigate to 'about:support' or 'about:firefox' to view the version number. On Linux distributions, you can also check the RPM/DEB package version with 'rpm -q firefox' or 'dpkg -s firefox'.

Affected if The exact version cannot be determined, assume potential exposure and investigate further.
Compare version against affected releases

Check if the installed version is exactly 61.x (any 61.x release) or ESR 60.1. Standard release Firefox 61.0.1, 61.0.2, etc. and Firefox ESR 60.1 are the vulnerable versions. Compare your version number to these.

Affected if Installed version is Firefox 61.x (any 61.x) or Firefox ESR 60.1, then the environment is directly affected by this CVE.
Check OS-supplied Firefox packages

On Red Hat Enterprise Linux 6/7, Debian 8/9, or Ubuntu 14.04/16.04/18.04 systems that ship Firefox via system packages, the vulnerable version may have been delivered through system updates. Check your package manager history or installed firefox package version with 'yum info firefox' (RHEL) or 'apt-cache policy firefox' (Debian/Ubuntu).

Affected if The system package manager shows Firefox version 61 or ESR 60.1 as installed, the system is affected.

If Firefox version 61 (any 61.x release) or Firefox ESR 60.1 is installed, either directly or via system packages on the listed distributions, the environment is vulnerable to memory corruption and potential code execution.

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

Remediation

dbcve · scoped

Mitigation available No clean upgrade yet — mitigate in the meantime

Mitigation

Upgrade to Firefox 62+, Firefox ESR 60.2+, or Thunderbird 60.2.1+ to patch the memory safety vulnerabilities.

Recommended fix High confidence

Firefox 62+, Firefox ESR 60.2+, or Thunderbird 60.2.1+

Identify which application is affected (Firefox or Thunderbird) by checking the installed version: `rpm -qa | grep -i firefox` or `rpm -qa | grep -i thunderbird`
For RHEL/CentOS systems: Run `sudo yum update firefox` or `sudo yum update thunderbird` to update to the fixed version
For Debian/Ubuntu systems: Run `sudo apt-get update && sudo apt-get install firefox` or `sudo apt-get update && sudo apt-get install thunderbird` to get the patched version
Verify the installed version meets the fixed release: Firefox >= 62, Firefox ESR >= 60.2, or Thunderbird >= 60.2.1
Restart the browser/application after updating

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

Fix this in Enterprise Linux Desktop Scoped from the published advisory

Consultation1.0 h
Implementation2.0 h
Testing1.0 h
Review / QA1.0 h

5.0 hours of engineering $890

Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,424.

Scan for this in your stack

Free · runs locally

dbcve dependency scanner

Check whether your project pulls in CVE-2018-12376 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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References

Primary sources

www.mozilla.orgVendor Advisory
www.mozilla.orgVendor Advisory
www.mozilla.orgVendor Advisory
www.securityfocus.comThird Party AdvisoryVDB Entry
www.securitytracker.comThird Party AdvisoryVDB Entry
access.redhat.comThird Party Advisory
access.redhat.comThird Party Advisory
access.redhat.comThird Party Advisory
access.redhat.comThird Party Advisory
bugzilla.mozilla.orgIssue TrackingThird Party Advisory
lists.debian.orgMailing ListThird Party Advisory
security.gentoo.orgThird Party Advisory
security.gentoo.orgThird Party Advisory
usn.ubuntu.comThird Party Advisory
usn.ubuntu.comThird Party Advisory
www.debian.orgThird Party Advisory
www.debian.orgThird Party Advisory
nvd.nist.govNVD record

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-12376 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2018-12376?

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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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

At a glance

A fix existsA vendor remedy is published

Severity 9.8 Critical

Exploit likelihood EPSS, next 30 days 3.1%

Affects: Enterprise Linux Desktop

Remediation

A high-priority fix

Fix this in Enterprise Linux Desktop 5 hrs · Low

Typical engagement from $890

Get a fix See the full breakdown ↓

A high-priority vulnerability. Send your environment and a specialist will scope CVE-2018-12376 and return a fixed quote and timeline.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

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.

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.

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.

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.

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.

Check your environment

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.

Scan for this in your stack

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

Practitioner notes

No notes yet

Official description

Technical summary

Affected products & versions

CVSS breakdown

Am I affected?

Remediation

References