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FirefoxWeb browser · Mozilla

CVE-2018-5093

HIGH · 7.5 CVSS v3.0 Published 2018-06-11
Fix available
A fix is available. Upgrade to after 57.0.4 or later.
See remediation →
84/100
Remediation priority · High
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 heap buffer overflow vulnerability may occur in WebAssembly during Memory/Table resizing, resulting in a potentially exploitable crash. This vulnerability affects Firefox < 58.

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 heap buffer overflow vulnerability exists in Firefox's WebAssembly implementation due to insufficient bounds checking during Memory or Table resizing operations. This can cause heap memory corruption leading to a potentially exploitable crash.

MitigationUpgrade Firefox to version 58 or later to obtain the vendor patch. Until then, consider disabling WebAssembly in browser settings or restricting access to untrusted WebAssembly content as a temporary workaround.

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:<= 57.0.4
Ubuntu LinuxOperating system
Affected:= 14.04= 16.04= 17.10

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
None
Integrity
None
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 installed Firefox version on Windows/Mac/Linux
    Open Firefox, click Menu > Help > About Firefox, or run 'firefox --version' from command line
    Affected if Version number displayed is 57.0.4 or lower
  2. Check Firefox version on Ubuntu systems
    Run 'dpkg -l | grep firefox' or 'apt-cache policy firefox' in terminal
    Affected if Installed firefox package version is 57.0.4 or lower (check the i386 or amd64 version entry)
  3. Verify WebAssembly is in use
    WebAssembly is enabled by default in affected Firefox versions. No configuration check needed - any user who loads WebAssembly content (common in modern web pages) triggers the vulnerable code path
    Affected if User loads or executes any WebAssembly module in the browser

User is affected if Firefox version is 57.0.4 or lower and the browser is used to execute WebAssembly code from any source.

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 a release after 57.0.4
Interim mitigation

Upgrade Firefox to version 58 or later to obtain the vendor patch. Until then, consider disabling WebAssembly in browser settings or restricting access to untrusted WebAssembly content as a temporary workaround.

Fix this in Firefox 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 the upgrade done

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

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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-2018-5093 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