CVE-2016-9838: Joomla!

High severity, CVSS 7.5. EPSS: 14.1% chance of exploitation in the next 30 days.

An issue was discovered in components/com_users/models/registration.php in Joomla! before 3.6.5. Incorrect filtering of registration form data stored to the session on a validation error enables a user to gain access to a registered user's account and reset the user's group mappings, username, and password, as demonstrated by submitting a form that targets the `registration.register` task.

Affected products

• Joomla! Joomla!: up to and including 3.6.4

Published 2016-12-16. Last modified 2026-06-17.