FirefoxWeb browser · Mozilla
CVE-2017-5399
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 · uneditedMemory safety bugs were reported in Firefox 51. Some of these bugs showed evidence of memory corruption and we presume that with enough effort that some of these could be exploited to run arbitrary code. This vulnerability affects Firefox < 52 and Thunderbird < 52.
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 confidenceMultiple memory safety bugs in Firefox 51 and Thunderbird 51 showed evidence of memory corruption. Researchers determined these vulnerabilities could potentially be exploited to run arbitrary code with sufficient effort.
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
< 52.0< 52.0CVSS 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
- 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 checksWork through these to decide whether this CVE applies to you.
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Check Firefox versionOpen Firefox and navigate to Help > About Firefox, or type 'about:firefox' in the address bar, or run 'firefox --version' in terminalAffected if The displayed version is below 52.0 (for example, 51.x or lower)
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Check Thunderbird versionOpen Thunderbird and navigate to Help > About Thunderbird, or type 'about:support' in the address bar, or run 'thunderbird --version' in terminalAffected if The displayed version is below 52.0 (for example, 51.x or lower)
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Verify package manager version (Linux)If installed via package manager, check with command: 'dpkg -l | grep firefox' or 'rpm -q firefox' for Red Hat-based systemsAffected if The installed package version listed is earlier than 52.0
If either Firefox or Thunderbird is installed at a version lower than 52.0, the system is affected by this memory corruption 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.
dbcve · scoped52.0
Update affected systems to Firefox 52 or later, and Thunderbird 52 or later, to patch the memory corruption vulnerabilities.
Firefox 52.0 or later / Thunderbird 52.0 or later
- Check current Firefox or Thunderbird version by navigating to Help > About (or using the command: firefox --version or thunderbird --version)
- Back up critical user data: bookmarks, passwords, and any local mail data to an external location
- Download Firefox 52.0 or later from the official Mozilla website (www.mozilla.org) or use your system's package manager
- For Thunderbird, download Thunderbird 52.0 or later from www.mozilla.org
- Run the installer and follow the prompts to complete the upgrade
- Restart the application and verify the version under Help > About to confirm the upgrade was successful
- For enterprise environments using automatic deployment, push Firefox ESR 52.x or later via your software distribution system
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Firefox
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 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 $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-5399 — 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-2017-5399 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
- No spam, self-promotion, credentials, or personal data