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Debian LinuxOperating system · Debian

CVE-2018-5155

CRITICAL · 9.8 CVSS v3.0 Published 2018-06-11
Fix available
A fix is available. Upgrade to 52.8.0 / 60.0 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges 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
A use-after-free vulnerability can occur while adjusting layout during SVG animations with text paths. This results in a potentially exploitable crash. This vulnerability affects Thunderbird < 52.8, Thunderbird ESR < 52.8, Firefox < 60, and Firefox ESR < 52.8.

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 use-after-free vulnerability exists in Mozilla Firefox and Thunderbird's layout engine when processing SVG animations that use text paths. During layout adjustment, memory for a previously freed object is accessed after it has been deallocated, leading to memory corruption and potentially exploitable crash conditions.

MitigationUpgrade affected installations to Firefox 60+, Firefox ESR 52.8+, Thunderbird 52.8+, or Thunderbird ESR 52.8+ to receive the patched version. Alternatively, disable SVG animations or restrict handling of SVG content with text paths until patching can be completed.

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:= 7.0= 8.0= 9.0
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
FirefoxWeb browser
Affected:< 52.8.0< 60.0

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
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? 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 Firefox version on Windows/macOS
    Open Firefox, click the menu button, go to Help > About Firefox. The version number is displayed in the window that opens.
    Affected if The version displayed is less than 52.8.0 or between 53.x and 59.x (less than 60.0)
  2. Check Thunderbird version on Windows/macOS
    Open Thunderbird, click the menu button, go to Help > About Thunderbird. The version number is displayed in the window that opens.
    Affected if The version displayed is less than 52.8.0 or between 53.x and 59.x (less than 60.0)
  3. Check Firefox version on Linux via command line
    Run 'firefox --version' or 'rpm -q firefox' (RHEL) or 'dpkg -l firefox' (Debian) in a terminal.
    Affected if The reported version is less than 52.8.0 or between 53.x and 59.x (less than 60.0)
  4. Check Thunderbird version on Linux via command line
    Run 'thunderbird --version' or 'rpm -q thunderbird' (RHEL) or 'dpkg -l thunderbird' (Debian) in a terminal.
    Affected if The reported version is less than 52.8.0 or between 53.x and 59.x (less than 60.0)
  5. Check Debian package versions for Firefox or Iceweasel
    Run 'dpkg -l | grep -i firefox' or 'dpkg -l | grep -i iceweasel' to list installed Mozilla package versions.
    Affected if The package version shown is 1:52.8.0-1~deb7u1, 1:52.8.0-1~deb8u1, or 1:52.8.0-1~deb9u1 (exact matches to Debian 7, 8, or 9)
  6. Check Red Hat Enterprise Linux package versions
    Run 'rpm -qa | grep -i firefox' or 'rpm -qa | grep -i thunderbird' to list installed Mozilla package versions.
    Affected if The package version matches the affected RHEL versions: 6.0 or 7.0 desktop/server/workstation, or 7.5/7.6 for Server EUS/Aus/Tus variants

You are affected if your installed Firefox or Thunderbird version is less than 52.8.0 or falls between 53.0 and 59.x, or if your Linux distribution package versions match the specific affected Debian or RHEL versions listed.

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 52.8.0 / 60.0 or later
Fixed in 52.8.060.0
Interim mitigation

Upgrade affected installations to Firefox 60+, Firefox ESR 52.8+, Thunderbird 52.8+, or Thunderbird ESR 52.8+ to receive the patched version. Alternatively, disable SVG animations or restrict handling of SVG content with text paths until patching can be completed.

Recommended fix High confidence

Firefox 60.0+ or Firefox ESR 52.8+; Thunderbird 52.8+ or Thunderbird ESR 52.8+

  1. 1. Identify the installed Firefox or Thunderbird version by navigating to Help > About (or using 'firefox --version' or 'thunderbird --version' in terminal)
  2. 2. If running Firefox < 60.0, upgrade to Firefox 60.0 or later (or Firefox ESR 52.8 or later for ESR users)
  3. 3. If running Thunderbird < 52.8, upgrade to Thunderbird 52.8 or later (or Thunderbird ESR 52.8 or later)
  4. 4. On Linux systems using distribution packages, run 'apt-get update && apt-get upgrade' (Debian) or 'yum update' (Enterprise Linux) to obtain the patched packages
  5. 5. After upgrade, restart the application and verify the version matches the fixed release
Caveat Minor - this is a security patch release; some legacy add-ons may be incompatible with Firefox 60+ if they have not been updated for the new extension API

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
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,600
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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-2018-5155 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