MoodleCMS
CVE-2018-1045
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 · uneditedIn Moodle 3.x, there is XSS via a calendar event name.
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 3.x contains a stored Cross-Site Scripting (XSS) vulnerability in the calendar event name field. An authenticated user with privileges to create calendar events can inject malicious JavaScript code that executes when other users view the calendar, allowing session hijacking or defacement.
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
<= 3.1.9= 3.2.0= 3.2.1= 3.2.2= 3.2.3= 3.2.4= 3.2.5= 3.2.6= 3.3.0= 3.3.1= 3.3.2= 3.3.3CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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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Determine Moodle installation versionLocate the version.php file in the Moodle root directory and read the $release or $version variable, or access the Site Administration > Server > Environment page to view the installed Moodle versionAffected if The installed version is <= 3.1.9, or one of 3.2.0 through 3.2.6, or one of 3.3.0 through 3.3.3
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Verify calendar module is enabledNavigate to Site Administration > Plugins > Plugins overview and confirm the Calendar module (mod_calendar) is installed and enabled, or check the modules table in the Moodle databaseAffected if The calendar module is enabled and accessible to users
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Confirm calendar event creation privileges existCheck user roles and capabilities at Site Administration > Users > Permissions > Define roles. Look for the capability mod/calendar:manageentries assigned to authenticated user rolesAffected if Any authenticated role has permission to create calendar events
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Inspect existing calendar events for suspicious contentQuery the mdl_event table in the Moodle database, examining the name field for HTML tags, script elements, or JavaScript event handlers. Alternatively, view the calendar at /calendar/view.php and inspect event names for unescaped HTMLAffected if Any calendar event names contain raw HTML, script tags, or JavaScript code that would execute when viewed
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Check browser console for XSS errors when viewing calendarLog in as a regular user, navigate to the calendar page, and open the browser developer console. Look for any script errors or unexpected behavior when viewing calendar eventsAffected if JavaScript executes or errors appear when viewing calendar event names
A user is affected if their Moodle installation runs a version within the listed ranges AND the calendar module is enabled with event creation capabilities available to authenticated users.
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 dataApply the vendor patch for CVE-2018-1045 which adds proper input sanitization and output encoding for calendar event names in Moodle 3.x.
Fix this in Moodle
Scoped from the published advisory
- Consultation2.0 h
- Implementation3.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-1045 — 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-2018-1045 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