CVE-2026-39878 chamilo-lms vulnerability
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.
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chamilo-lms should be reviewed and updated if it matches the affected versions. The recommended fix is to apply the vendor-supported patched version or the mitigation steps below, then retest the public website with Fixnx.
Who is affected
Affected versions
- <= 1.11.38
Fixed versions
- Apply the latest vendor-supported patched version.
How to fix it
CVE-2026-39878 affects chamilo-lms and involves cross-site scripting. Successful exploitation may run attacker-controlled script in a trusted user's browser and expose session or application data. Treat this as a high-priority fix, especially when the affected component or endpoint is reachable by untrusted users. Upgrade Chamilo LMS to 1.11.40 or later.
- Inventory every deployment, device, package, plugin, container, build, and environment that uses chamilo-lms.
- Compare the installed version with the recorded affected range: <= 1.11.38.
- Upgrade Chamilo LMS to 1.11.40 or later.
- Until patched, reduce public exposure, disable the affected workflow where practical, and allow access only from trusted users and systems.
- Review configuration, roles, tokens, network paths, and exposed endpoints connected to chamilo-lms; remove access that is not required.
- Review submissions, stored content, administrator activity, CSP reports, and web logs for script payloads or suspicious browser requests.
- If exploitation is suspected, isolate affected assets, preserve evidence, rotate exposed credentials or keys, restore trusted data, and rebuild compromised systems before returning them to service.
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Verify the fix
- Confirm every affected asset now runs the fixed vendor-supported release or has the documented mitigation for CVE-2026-39878 in place.
- Use a safe regression test to confirm the affected cross-site scripting path no longer produces the vulnerable behavior.
- Confirm temporary access controls, endpoint restrictions, network blocks, and least-privilege settings remain effective after the update.
- Review post-remediation logs and rerun Fixnx plus the relevant package, dependency, firmware, browser, or product-specific security check.
- Document affected assets, versions, changes, validation evidence, reviewed logs, and any credential rotation, cleanup, or replacement completed.
Related categories
Related security risks
More published guidance from the same primary category.
Trusted references
FAQ
What is affected by CVE-2026-39878?
chamilo-lms versions listed as affected should be reviewed: <= 1.11.38.
What should I fix first?
Start with internet-facing sites, admin panels, login flows, plugins, themes, modules, packages, and systems that process user-controlled input or sensitive data.
How do I confirm the fix worked?
Apply the patched version or mitigation, clear caches where relevant, retest the affected workflow, and run a new Fixnx scan to verify public website exposure signals.
How are Fixnx security risk categories chosen?
Fixnx keeps one canonical risk page and assigns only broad, relevant categories such as ecosystem, technology area, or vulnerability class.