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MoodleCMS

CVE-2018-1135

MEDIUM · 6.5 CVSS v3.0 Published 2018-05-25
Fix available
A fix is available. Upgrade to after 3.4.2 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable Zero-click

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 · unedited
An issue was discovered in Moodle 3.x. Students who posted on forums and exported the posts to portfolios can download any stored Moodle file by changing the download URL.

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 confidence

This is an Insecure Direct Object Reference (IDOR) vulnerability in Moodle 3.x where students who post on forums and export posts to portfolios can manipulate download URLs to access any file stored in Moodle, bypassing intended access controls. The portfolio export functionality fails to validate that the requesting user has permission to download the specific file referenced in the URL.

MitigationImplement proper authorization checks in the portfolio file download functionality to verify the user has permission to access the requested file before serving it. This requires validating the file ownership/permissions against the current user's access rights.

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
Affected:>= 3.1.0, <= 3.1.11>= 3.2.0, <= 3.2.8>= 3.3.0, <= 3.3.5>= 3.4.0, <= 3.4.2

CVSS 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
High
Integrity
None
Availability
None

CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/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 checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Moodle version
    Log in as admin and navigate to Site Administration > Server > Environment, or check the version.php file in the Moodle root directory (look for $release or $version variables)
    Affected if The installed 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
  2. Verify portfolio module is enabled
    Navigate to Site Administration > Plugins > Manage portfolios. Confirm the portfolio plugin system is enabled and at least one portfolio export format (such as File download, Moodle XML, or others) is active
    Affected if The portfolio module is enabled and configured for use
  3. Verify forum module is active
    Navigate to Site Administration > Plugins > Activity modules > Manage activities. Confirm the Forum activity module is installed and visible across the site
    Affected if The forum activity module is installed and available to users
  4. Inspect portfolio download handler for authorization check
    Locate the portfolio file download script (typically in /portfolio/ directory). Examine the code that handles file retrieval to verify if it performs user capability checks on the file being requested before serving it. Look for calls to functions like require_capability or file_access_control
    Affected if The portfolio download handler lacks proper capability checks before serving files, allowing unauthenticated or unauthorized file access

If the Moodle version is within the affected ranges AND the portfolio and forum modules are enabled, and the code lacks authorization validation in the portfolio download handler, the system is vulnerable to this IDOR flaw.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Upgrade available Upgrade to a release after 3.4.2
Interim mitigation

Implement proper authorization checks in the portfolio file download functionality to verify the user has permission to access the requested file before serving it. This requires validating the file ownership/permissions against the current user's access rights.

Fix this in Moodle Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-1135 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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