Joomla\!Application · Joomla
CVE-2018-15882
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 issue was discovered in Joomla! before 3.8.12. Inadequate checks in the InputFilter class could allow specifically prepared phar files to pass the upload filter.
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 InputFilter class in Joomla! before 3.8.12 lacked adequate validation to block phar (PHP archive) file uploads. This allowed attackers to upload specially crafted phar files that could be leveraged for PHP object injection attacks, potentially leading to remote code execution. The vulnerability stems from the filter not properly detecting and rejecting phar file signatures during the upload validation process.
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
Joomla\!Application
< 3.8.12CVSS 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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Determine Joomla versionLocate the version.php file in your Joomla installation (typically in /libraries/cms/version.php or check the admin dashboard footer), or query the database version table if accessibleAffected if The installed version is any release before 3.8.12 (e.g., 3.8.11, 3.8.10, etc.)
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Verify if file uploads are enabledCheck the Joomla global configuration in the administrator panel under System > Global Configuration > Site tab, or inspect configuration.php for the $upload_max_filesize setting and $enable_upload settingAffected if File uploads are enabled (value is 1 or a non-zero filesize is set)
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Inspect upload directories for phar filesUse file system search commands (such as find, ls, or dir) to locate any .phar files within the Joomla uploads directory (typically /images or /media)Affected if Any .phar files exist in upload directories, indicating potential exploitation
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Review InputFilter usage in upload handling codeIf you have access to the source code, search for instances where the InputFilter class is used to validate file uploads, particularly looking at how the phar signature is (or is not) being checkedAffected if The InputFilter class is being used but phar file type detection is not implemented in the validation logic
Your environment is affected if you are running Joomla! version 3.8.11 or earlier AND file uploads are enabled, regardless of whether you detect malicious phar files already 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.
dbcve · scoped3.8.12
Upgrade Joomla! to version 3.8.12 or later. As an immediate workaround, restrict file upload permissions and disable PHP execution in upload directories to limit exposure until the patch can be applied.
Joomla! 3.8.12 or later
- Create a complete backup of your Joomla! site including database and all files
- Ensure you have FTP or file system access to your Joomla! installation
- Download Joomla! 3.8.12 (or latest 3.x release) from the official Joomla! Downloads page (downloads.joomla.org)
- Extract the update package to your local system
- Upload the extracted files to your Joomla! root directory, overwriting existing files
- Clear any caching mechanisms after the update
- Verify the update was successful by checking the Joomla! Administrator dashboard for version 3.8.12 or later
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Joomla\!
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,888.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-15882 — 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-2018-15882 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