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Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-39878

CRITICAL · 9.3 CVSS v3.1 Published 2026-07-20
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges 4 weeks old

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
Chamilo LMS versions 1.11.38 and earlier contain a stored cross-site scripting vulnerability in the user registration form that allows any unauthenticated attacker to execute arbitrary JavaScript in an administrator's browser session, leading to full platform admin account takeover. This has been patched in 1.11.40.

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

Chamilo LMS versions 1.11.38 and earlier contain a stored cross-site scripting vulnerability in the user registration form. Unauthenticated attackers can inject malicious JavaScript payloads into registration fields that persist in the system. When administrators view the registration data in the admin panel, the payload executes, allowing session hijacking and full admin account takeover.

MitigationUpgrade Chamilo LMS to version 1.11.40 or later to apply the security patch. Consider reviewing admin access logs for suspicious activity since the vulnerability was exploitable by unauthenticated attackers.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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
None
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/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. Confirm Chamilo LMS installation
    Access the admin panel or check the main configuration file (typically version.php or config.php in the main directory) to identify the installed Chamilo LMS version number.
    Affected if The version displayed is 1.11.38 or any earlier version (1.11.x series below 1.11.38).
  2. Verify user registration is enabled
    Log into the Chamilo admin panel and navigate to the portal settings or administration > configuration settings. Look for the registration/enable_registration setting.
    Affected if User self-registration is set to 'enabled' or 'true', allowing unauthenticated users to submit the registration form.
  3. Inspect user profile data for injected scripts
    Access the admin panel's user management section (Administration > User list). Review the first_name, last_name, and email fields of recently registered users for unusual characters or script tags (<script>, javascript:, onload, etc.).
    Affected if Any user profiles contain suspicious HTML/JavaScript code patterns in name or email fields that were not intentionally entered by administrators.
  4. Check server logs for registration form abuse
    Review web server access logs (Apache/nginx) for POST requests to the registration endpoint (typically /main/auth/registration.php) with unusual payload patterns.
    Affected if Multiple registration submissions from various IP addresses contain encoded JavaScript or script tags in input fields.

A Chamilo LMS installation is affected if it runs version 1.11.38 or earlier with user registration enabled, regardless of whether exploitation is currently observable.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Chamilo LMS to version 1.11.40 or later to apply the security patch. Consider reviewing admin access logs for suspicious activity since the vulnerability was exploitable by unauthenticated attackers.

Recommended fix High confidence

Chamilo LMS 1.11.40

  1. Obtain Chamilo LMS version 1.11.40 from the official source
  2. Create a complete backup of the current Chamilo installation and database
  3. Upgrade the existing Chamilo LMS installation to version 1.11.40
  4. Verify the upgrade was successful and confirm the version in the administration panel

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing6.0 h
  • Review / QA3.0 h
19.0 hours of engineering $3,320
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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-2026-39878 in production — separate from our analysis above.

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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
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  • Version or environment caveats, and links to real fixes
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