Joomla\!Application · Joomla
CVE-2018-17856
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 3.8.13. com_joomlaupdate allows the execution of arbitrary code. The default ACL config enabled the ability of Administrator-level users to access com_joomlaupdate and trigger code execution.
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 com_joomlaupdate component in Joomla! versions before 3.8.13 contained a vulnerability allowing Administrator-level users to execute arbitrary code through the update functionality. The default ACL configuration permitted access to this component, enabling authenticated administrators to trigger code execution.
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
>= 2.5.4, < 3.8.13CVSS 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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Determine installed Joomla! versionLocate the version.php file in the Joomla installation (typically at /libraries/cms/version.php) or check the VERSION file in the root directory. Open the file and read the VERSION and REVISION constants, or the version string directly.Affected if The installed version is greater than or equal to 2.5.4 AND less than 3.8.13 (for example, 3.8.0 through 3.8.12 are affected).
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Verify com_joomlaupdate component existsCheck for the com_jojaupdate component directory at /administrator/components/com_joomlaupdate/ and verify the component is listed in the #__extensions table of the database with enabled=1.Affected if The component is present and enabled, which is the default configuration in affected versions.
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Confirm administrator-level user accessCheck the #__user_usergroup_map table in the Joomla database to identify users assigned to groups with administrative privileges (typically group ID 7 or 8, representing Administrator or Super Administrator).Affected if An authenticated user with Administrator-level privileges exists in the system, as this CVE requires admin-level access to exploit.
If the Joomla installation version falls within 2.5.4 through 3.8.12 AND the com_joomlaupdate component is enabled AND an administrator-level user account exists, the environment is vulnerable to CVE-2018-17856.
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 data3.8.13
Upgrade Joomla! to version 3.8.13 or later to patch this vulnerability. Alternatively, restrict access to the com_joomlaupdate component through ACL configuration until the patch can be applied.
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-2018-17856 — 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-2018-17856 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