CVE-2017-12756
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 · uneditedCommand inject in transfer from another server in extplorer 2.1.9 and prior allows attacker to inject command via the userfile[0] parameter.
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 confidenceCommand injection vulnerability in extplorer 2.1.9 and prior allows attackers to inject arbitrary OS commands through the userfile[0] parameter during file transfer operations from external servers. The parameter is not properly sanitized before being used in a system call.
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<= 2.1.9CVSS 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
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:H/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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Locate extplorer installation and determine versionSearch for extplorer files in your web root and check for a version file, about page, or the main index script that displays the version number. Common paths include /extplorer/, /administrator/components/com_extplorer/, or check the extplorer/config.php file for version info.Affected if The installed version is extplorer 2.1.9 or any version prior to 2.1.9
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Identify if the file transfer from external servers feature is accessibleDetermine whether the extplorer application is exposed to the web and whether the functionality to transfer files from external servers (often found in the transfer or ftp import sections) is enabled and accessible to users.Affected if The extplorer transfer-from-server feature is enabled and reachable by untrusted users or anonymous visitors
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Check application accessibilityVerify whether extplorer is publicly accessible without authentication or accessible to low-privilege users who could supply the userfile[0] parameter.Affected if Untrusted or low-privilege users can access extplorer and reach the vulnerable file transfer functionality
You are affected if extplorer version 2.1.9 or lower is installed AND the external file transfer feature using the userfile[0] parameter is accessible to untrusted users.
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 dataUpdate to a patched version of extplorer if available. If no patch exists, implement strict input validation and sanitization on the userfile[0] parameter to prevent command injection, or disable the vulnerable transfer-from-server functionality.
- Consultation2.0 h
- Implementation3.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-12756 — 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-2017-12756 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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