FirefoxWeb browser · Mozilla
CVE-2018-18503
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 · uneditedWhen JavaScript is used to create and manipulate an audio buffer, a potentially exploitable crash may occur because of a compartment mismatch in some situations. This vulnerability affects Firefox < 65.
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 · moderate confidenceA compartment mismatch vulnerability in Firefox allows JavaScript to trigger a potentially exploitable crash when creating and manipulating audio buffers. The flaw occurs when security compartments conflict during audio buffer operations, which can lead to memory corruption and potential code execution.
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
< 65.0
Ubuntu LinuxOperating system
= 14.04= 16.04= 18.04= 18.10CVSS 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
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/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 checksWork through these to decide whether this CVE applies to you.
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Check Firefox browser versionOpen Firefox, navigate to Help > About Firefox, or type about:firefox in the address bar. Note the version number displayed.Affected if The displayed version is less than 65.0 (for example, 64.0, 64.0.1, 64.1, etc.)
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Check Firefox package version on Ubuntu (if applicable)Run command: dpkg -l firefox | grep firefox or apt list --installed 2>/dev/null | grep firefox. The output will show the installed package version.Affected if The package version number shown is less than 65.0 (for example, 64.0.x or similar). Note that Ubuntu may backport security fixes, so also check if the Ubuntu security notice USN-4561-1 has been applied.
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Verify if audio buffer operations are in useThis vulnerability triggers when JavaScript creates or manipulates Web Audio API buffers. Check any web applications or browser-based audio tools currently running in the browser.Affected if Active web content is using the Web Audio API (AudioContext, AudioBuffer, or related interfaces) while running a vulnerable Firefox version.
If Firefox version is below 65.0 and any Web Audio API operations are performed, the environment is affected by this vulnerability.
Generated from the published advisory. Verify against your own configuration.
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 data65.0
Upgrade Firefox to version 65 or later to remediate this vulnerability.
Fix this in Firefox
Scoped from the published advisory
- Consultation1.0 h
- Implementation1.0 h
- Testing1.0 h
- Review / QA1.0 h
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 locallyCheck whether your project pulls in CVE-2018-18503 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2018-18503 in production — separate from our analysis above.
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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- 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
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