FirefoxWeb browser · Mozilla
CVE-2024-5694
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 · uneditedAn attacker could have caused a use-after-free in the JavaScript engine to read memory in the JavaScript string section of the heap. This vulnerability affects Firefox < 127.
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 confidenceUse-after-free vulnerability in Firefox's JavaScript engine allows an attacker to read heap memory in the JavaScript string section, potentially exposing sensitive data or facilitating further exploitation.
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
< 127.0CVSS 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
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
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 if Firefox is installedLook for Firefox in your system applications or check common installation paths (e.g., /Applications on macOS, C:\Program Files\Mozilla Firefox on Windows, or your Linux distribution's package manager)Affected if Firefox is not found on the system, then this CVE does not apply
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Identify the installed Firefox versionOpen Firefox, go to Help > About Firefox, or run 'firefox --version' from command line, or check your system's installed packages listAffected if The version displayed is lower than 127 (for example, 126.x, 125.x, or earlier)
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Confirm the JavaScript engine is in useThis vulnerability exists in Firefox's JavaScript engine (SpiderMonkey). Any normal web browsing or JavaScript execution triggers the JS engineAffected if Firefox is used for web browsing with JavaScript enabled, which is the default behavior
You are affected if Firefox is installed and the version is below 127, since the use-after-free flaw in the JavaScript engine triggers during normal browser use with JavaScript enabled.
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.
dbcve · scoped127.0
Update Firefox to version 127 or later to patch the use-after-free vulnerability in the JavaScript engine.
Firefox 127
- Open Firefox and click the menu button (three horizontal lines) in the top-right corner
- Select 'Help' from the menu, then click 'About Firefox'
- The About Firefox window will open and automatically check for updates
- If an update is available, click 'Update to Firefox 127' or allow it to download automatically
- After the download completes, click 'Restart to update Firefox'
- Verify the update was successful by returning to Help > About Firefox and confirming version 127 is installed
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Firefox
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 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 $1,424.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2024-5694 — 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-2024-5694 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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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.
- 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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