Moodle 4.2.0 through 4.5.15, 5.0.0 through 5.0.11, 5.1.0 through 5.1.8, 5.2.0 through 5.2.4, and 5.3.0 contain an information disclosure vulnerability in the core_grades_get_feedback web service. The service lacks group-membership and enrolment checks, so non-editing teachers can iterate userid values to read other groups' grade feedback and users' names and identity fields such as email.
https://github.com/moodle/moodle/blob/v5.3.0/public/grade/classes/external/get_feedback.php#L77-L96
https://github.com/moodle/moodle
https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-113820
https://abraxaslabs.tech/research/moodle-grades-feedback-idor
Published: 2026-10-30
Updated: 2026-10-30
Base Score: 4
Vector: CVSS2#AV:N/AC:L/Au:S/C:P/I:N/A:N
Severity: Medium
Base Score: 4.3
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Severity: Medium
Base Score: 5.3
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00217