CVE-2023-23923: Moodle: possible to set the preferred "start page" of other users

Severity: high (CVSS 8.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-02-17 · updated 2026-06-17
Weakness: CWE-284

Description

The vulnerability was found Moodle which exists due to insufficient limitations on the "start page" preference. A remote attacker can set that preference for another user. The vulnerability allows a remote attacker to gain unauthorized access to otherwise restricted functionality.

Affected products

Moodle: from 3.9.0 before 3.9.19; from 3.11.0 before 3.11.12; from 4.0.0 before 4.0.6; 4.1.0 — fixed in 3.11.12, 3.9.19, 4.0.6

How to fix

Upgrade to a fixed version: Moodle 3.11.12, 3.9.19, 4.0.6. Check the vendor advisory for mitigations.

References

http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-76862
https://bugzilla.redhat.com/show_bug.cgi?id=2162549
https://moodle.org/mod/forum/discuss.php?d=443274#p1782023
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-76862
https://bugzilla.redhat.com/show_bug.cgi?id=2162549
https://moodle.org/mod/forum/discuss.php?d=443274#p1782023

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