Joomla\!Application · Joomla
CVE-2021-26031
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! 3.0.0 through 3.9.25. Inadequate filters on module layout settings could lead to an LFI.
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 confidenceInadequate input filtering on Joomla module layout settings allows authenticated attackers (or potentially unauthenticated depending on configuration) to perform Local File Inclusion (LFI), enabling reading of sensitive files on the server through path traversal in the module layout parameter.
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
>= 3.0.0, <= 3.9.25CVSS 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
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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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Confirm Joomla versionLocate and read the Joomla version file (typically found in the administrator/manifests/files_joomla.xml or via the administrator About page). Extract the installed version number.Affected if The installed version falls within >= 3.0.0 and <= 3.9.25
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Verify module configuration accessDetermine whether the Joomla modules management interface (typically at /administrator/index.php?option=com_modules) is accessible. This could be via admin authentication or, depending on Joomla configuration, potentially exposed to unauthenticated users.Affected if The modules interface is reachable without proper access controls, allowing modification of module layout parameters
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Identify module layout parameterIn the module editor (edit any module), locate the layout parameter field (often found under the Options or Details tab). This parameter accepts a path value that can be manipulated for path traversal.Affected if The layout parameter accepts arbitrary path input without sanitization, allowing characters like ../ to traverse directories
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Test path traversal capabilityAttempt to modify a module's layout parameter value to include a path traversal sequence (for example: ../../../../etc/passwd) and observe if the application accepts and processes this input.Affected if The application accepts unfiltered path traversal sequences in the layout parameter without rejecting or sanitizing them
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Check for sensitive file exposureIf the layout parameter accepts traversal, attempt to read a known sensitive file (such as the Joomla configuration.php containing database credentials) using a constructed path like ../../configuration.php from a typical module path.Affected if The server returns file contents from the constructed path, confirming the LFI vulnerability is exploitable
Your environment is affected if Joomla version is 3.0.0 through 3.9.25 AND the module layout parameter accepts unsanitized path traversal input, allowing unauthorized file read access.
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 dataUpgrade Joomla to version 3.9.26 or later which contains proper input filtering fixes for the module layout settings.
Fix this in Joomla\!
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 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 $1,664.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-26031 — 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-2021-26031 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
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