dbcve.org
FirefoxWeb browser · Mozilla

CVE-2008-5014

HIGH · 10.0 CVSS v2.0 Published 2008-11-13
Fix available
A fix is available. Upgrade to 1.1.13 / 2.0.0.18 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
jslock.cpp in Mozilla Firefox 3.x before 3.0.2, Firefox 2.x before 2.0.0.18, Thunderbird 2.x before 2.0.0.18, and SeaMonkey 1.x before 1.1.13 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code by modifying the window.__proto__.__proto__ object in a way that causes a lock on a non-native object, which triggers an assertion failure related to the OBJ_IS_NATIVE function.

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

This is a JavaScript engine vulnerability in the js lock mechanism (jslock.cpp). By manipulating the prototype chain through window.__proto__.__proto__, an attacker can cause a lock to be placed on a non-native object, triggering an assertion failure in the OBJ_IS_NATIVE function. This leads to denial of service (crash) and potentially arbitrary code execution.

MitigationApply vendor patches by updating to Firefox 3.0.2+, Firefox 2.0.0.18+, Thunderbird 2.0.0.18+, or SeaMonkey 1.1.13+. Disable JavaScript as a workaround if immediate patching is not possible.

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
FirefoxWeb browser
Affected:>= 2.0, < 2.0.0.18>= 3.0, < 3.0.2
Debian LinuxOperating system
Affected:= 4.0
Ubuntu LinuxOperating system
Affected:= 6.06= 7.10= 8.04= 8.10
SeamonkeyApplication
Affected:>= 1.0, < 1.1.13
ThunderbirdApplication
Affected:>= 2.0, < 2.0.0.18

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
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:L/Au:N/C:C/I:C/A:C

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. Identify the installed Mozilla product
    Check the installed application: Firefox, Thunderbird, or SeaMonkey. On Windows, check Add/Remove Programs or the application properties. On Linux, check the package manager (dpkg -l, rpm -qa, or similar).
    Affected if The product is Firefox, Thunderbird, or SeaMonkey and the version falls within the affected ranges.
  2. Determine the installed Firefox version
    For Firefox: Open Help > About Firefox, or run 'firefox -v' from command line, or check the version file in the installation directory.
    Affected if Version is >= 2.0.0 and < 2.0.0.18, or >= 3.0 and < 3.0.2.
  3. Determine the installed Thunderbird version
    For Thunderbird: Open Help > About Thunderbird, or run 'thunderbird -v' from command line, or check the package information.
    Affected if Version is >= 2.0 and < 2.0.0.18.
  4. Determine the installed SeaMonkey version
    For SeaMonkey: Open Help > About SeaMonkey, or check the package information via the system package manager.
    Affected if Version is >= 1.0 and < 1.1.13.
  5. Check if JavaScript is enabled in the browser
    In Firefox/SeaMonkey: Check Options > Content > Enable JavaScript. In Thunderbird: Check Edit > Preferences > Security > Enable JavaScript (note: Thunderbird may have JavaScript disabled by default in some versions).
    Affected if JavaScript is enabled. The vulnerability exists in the JavaScript engine, so it is only exploitable when JavaScript is enabled.

You are affected if you have Firefox < 2.0.0.18 or < 3.0.2, Thunderbird < 2.0.0.18, SeaMonkey < 1.1.13, AND JavaScript is enabled in the application settings.

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 1.1.13 / 2.0.0.18 / 3.0.2 or later
Fixed in 1.1.132.0.0.183.0.2
Interim mitigation

Apply vendor patches by updating to Firefox 3.0.2+, Firefox 2.0.0.18+, Thunderbird 2.0.0.18+, or SeaMonkey 1.1.13+. Disable JavaScript as a workaround if immediate patching is not possible.

Recommended fix High confidence

Firefox 2.0.0.18+ / Firefox 3.0.2+ / SeaMonkey 1.1.13+ / Thunderbird 2.0.0.18+

  1. Identify which Mozilla product is affected (Firefox, Thunderbird, or SeaMonkey)
  2. Check current installed version by accessing the application's 'About' menu
  3. For Firefox 2.x users: Upgrade to Firefox 2.0.0.18 or later
  4. For Firefox 3.x users: Upgrade to Firefox 3.0.2 or later
  5. For Thunderbird 2.x users: Upgrade to Thunderbird 2.0.0.18 or later
  6. For SeaMonkey 1.x users: Upgrade to SeaMonkey 1.1.13 or later
  7. Restart the application after upgrade
  8. Verify the version by checking the 'About' menu to confirm the fix is applied
Caveat Security updates should have minimal breaking changes; however, some older extensions or add-ons may be incompatible with newer versions

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

Fix this in Firefox Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2008-5014 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2008-5014 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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