The vulnerability was found Moodle which exists due to insufficient sanitization of user-supplied data in some returnurl parameters. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website. This flaw allows a remote attacker to perform cross-site scripting (XSS) attacks.

The link to update all installed language packs did not include the necessary token to prevent a CSRF risk.

Insufficient checks in a web service made it possible to add comments to the comments block on another user's dashboard when it was not otherwise available (e.g., on their profile page).

The URL parameters accepted by forum search were not limited to the allowed parameters.

Insufficient file size checks resulted in a denial of service risk in the file picker's unzip functionality.

Separate Groups mode restrictions were not honored when performing a forum export, which would export forum data for all groups. By default this only provided additional access to non-editing teachers.

Separate Groups mode restrictions were not honored in the H5P attempts report, which would display users from other groups. By default this only provided additional access to non-editing teachers.