FirefoxWeb browser · Mozilla
CVE-2019-17009
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 running, the updater service wrote status and log files to an unrestricted location; potentially allowing an unprivileged process to locate and exploit a vulnerability in file handling in the updater service. *Note: This attack requires local system access and only affects Windows. Other operating systems are not affected.*. This vulnerability affects Thunderbird < 68.3, Firefox ESR < 68.3, and Firefox < 71.
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 confidenceThe Firefox/Thunderbird updater service writes status and log files to an unrestricted location on Windows systems. A local unprivileged attacker with system access could manipulate these files to exploit file handling vulnerabilities in the updater service, potentially escalating privileges.
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
< 71.0
Firefox EsrWeb browser
< 68.3< 68.3= 15.1CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/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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Identify installed Mozilla productCheck if Firefox or Thunderbird is installed on the system by reviewing installed programs or locating the application executableAffected if Neither Firefox nor Thunderbird is installed - the system is not affected by this CVE
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Determine the installed versionOpen the application and navigate to Help > About (or use command line: 'firefox --version' or 'thunderbird --version' if available) to find the exact version numberAffected if Version is Firefox < 71.0, Firefox ESR < 68.3, or Thunderbird < 68.3 - the system is potentially affected
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Confirm operating systemCheck if the system is running Windows (this vulnerability specifically affects Windows implementations of the updater service)Affected if Running on Windows - the vulnerability applies; on non-Windows systems the specific flaw does not exist as described
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Verify updater service presenceOn Windows, check if the Mozilla update service is installed by reviewing Windows Services (services.msc) for entries like 'Firefox Update' or 'Mozilla Maintenance Service'Affected if The updater service is present and running - it could be exploited; however, even without the service, the file writing issue may still exist in older versions
If running Firefox below 71.0, Firefox ESR below 68.3, or Thunderbird below 68.3 on Windows, the system is vulnerable to CVE-2019-17009.
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 data68.371.0
Upgrade to Firefox >= 71, Firefox ESR >= 68.3, or Thunderbird >= 68.3. For enterprises, deploy the update via patch management and verify the installed version.
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-2019-17009 — 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-2019-17009 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