CVE-2017-16798
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 · uneditedIn CMS Made Simple 2.2.3.1, the is_file_acceptable function in modules/FileManager/action.upload.php only blocks file extensions that begin or end with a "php" substring, which allows remote attackers to bypass intended access restrictions or trigger XSS via other extensions, as demonstrated by .phtml, .pht, .html, or .svg.
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 confidenceIn CMS Made Simple 2.2.3.1, the is_file_acceptable function in the FileManager module's upload action performs inadequate extension filtering by only blocking extensions that begin or end with 'php', allowing dangerous extensions like .phtml, .pht, .svg, and .html to bypass the check. This enables remote attackers to upload malicious files containing PHP code or XSS payloads.
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= 2.2.3.1CVSS 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
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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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Verify CMS Made Simple version 2.2.3.1 is installedCheck the admin dashboard footer for the version number, or inspect the /lib/version.php file for the $CMS_VERSION variable.Affected if The installed version is exactly 2.2.3.1
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Confirm FileManager module is presentNavigate to the modules section in the admin panel, or check for the FileManager directory in /modules/Affected if The FileManager module is installed and enabled
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Inspect the is_file_acceptable function filtering logicLocate the FileManager module code (typically in /modules/FileManager/action.upload.php or similar) and examine the is_file_acceptable function for extension validation logic.Affected if The function only checks for extensions beginning or ending with 'php' and does not block .phtml, .pht, .svg, or .html extensions
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Verify upload functionality is accessible to the userLog in to the CMS as a user with access to the FileManager and attempt to access the file upload feature.Affected if The upload action in FileManager is accessible and the weak extension filtering is in use
A user is affected if they are running version 2.2.3.1 with the FileManager module enabled and the vulnerable extension filtering code is present.
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 dataReplace the weak extension filtering with a strict allowlist approach that explicitly permits only safe, non-executable file types and rejects all others, while ensuring .svg and other XML-based files are properly sanitized before upload.
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 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 $2,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-16798 — 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-2017-16798 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
- No spam, self-promotion, credentials, or personal data