MoodleCMS
CVE-2018-1137
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 Moodle 3.x. By substituting URLs in portfolios, users can instantiate any class. This can also be exploited by users who are logged in as guests to create a DDoS attack.
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 confidenceMoodle's portfolio subsystem allows users to substitute URLs that can be used to instantiate arbitrary PHP classes. This insecure deserialization/object injection vulnerability can be triggered even by guest users, allowing them to abuse the server resources for DDoS attacks or potentially achieve remote code execution through class instantiation.
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
MoodleCMS
>= 3.1.0, <= 3.1.11>= 3.2.0, <= 3.2.8>= 3.3.0, <= 3.3.5>= 3.4.0, <= 3.4.2CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/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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Check your Moodle versionOpen the file /lib/version.php in your Moodle installation directory and look for the $release or $version variable, or navigate to Site Administration > Server > Environment to see the installed version number.Affected if The version falls within 3.1.0-3.1.11, 3.2.0-3.2.8, 3.3.0-3.3.5, or 3.4.0-3.4.2.
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Verify the portfolio subsystem is enabledNavigate to Site Administration > Plugins > Manage portfolios, or check the 'portfoliolib.php' file in /lib/ directory for active portfolio plugins. Look for the 'enabled' setting.Affected if Any portfolio plugin (such as File download, Google Docs, Flickr, etc.) is enabled and active.
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Confirm guest login access is permittedNavigate to Site Administration > Plugins > Authentication > Manage authentication and verify whether the 'Guest login button' is enabled, or inspect the 'auth' setting in /config.php for guest access configuration.Affected if Guest access is enabled, allowing unauthenticated users to access the system.
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Check portfolio module visibility to guestsInspect the portfolio plugin configuration at Site Administration > Plugins > Manage portfolios and verify if portfolio functionality is exposed to guest users, or check the 'portfolio' capability in Site Administration > Users > Permissions > Define roles.Affected if Guest users have permission to use or access the portfolio functionality.
You are affected if your Moodle version matches the vulnerable ranges AND the portfolio subsystem is enabled AND guest users can access it, because the deserialization flaw can be triggered by unauthenticated guests through the portfolio URL substitution mechanism.
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 to a patched Moodle version. As a workaround, disable the portfolio plugin and guest login access until the patch can be applied.
Fix this in Moodle
Scoped from the published advisory
- Consultation4.0 h
- Implementation6.0 h
- Testing4.0 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 $4,832.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-1137 — 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-2018-1137 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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