calendar/externallib.php in Moodle through 2.6.11, 2.7.x before 2.7.13, 2.8.x before 2.8.11, 2.9.x before 2.9.5, and 3.0.x before 3.0.3 provides calendar-event data without considering whether an activity is hidden, which allows remote authenticated users to obtain sensitive information via a web-service request.
Severity
CVSS 3.0
4.3 medium
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
EPSS
1.7% chance of exploitation in the next 30 days; higher than 77% of CVEs (scores of 2026-10-31)