CVE-2021-47857: Moodle

Medium severity, CVSS 6.1. EPSS: 0.4% chance of exploitation in the next 30 days.

Moodle 3.10.3 contains a persistent cross-site scripting vulnerability in the calendar event subtitle field that allows attackers to inject malicious scripts. Attackers can craft a calendar event with malicious JavaScript in the subtitle track label to execute arbitrary code when users view the event.

Affected products

• Moodle Moodle: version 3.10.3 only

Published 2026-01-21. Last modified 2026-06-17.