CVE-2023-28333: Moodle: pix helper potential mustache code injection risk

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-03-23 · updated 2026-06-17
Weakness: CWE-94

Description

The Mustache pix helper contained a potential Mustache injection risk if combined with user input (note: This did not appear to be implemented/exploitable anywhere in the core Moodle LMS).

Affected products

Fedoraproject Fedora: 36
Moodle: from 3.9.0 (excl.) before 3.9.20; from 3.11.0 (excl.) before 3.11.13; from 4.0.0 (excl.) before 4.0.7; 3.9.0, 3.11.0, 4.0.0, 4.1.0, 4.1.1 — fixed in 3.11.13, 3.9.20, 4.0.7

How to fix

Upgrade to a fixed version: Moodle 3.11.13, 3.9.20, 4.0.7. Check the vendor advisory for mitigations.

References

https://bugzilla.redhat.com/show_bug.cgi?id=2179422
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3QZN34VSF4HTCW3C3ZP2OZYSLYUKADPF/
https://moodle.org/mod/forum/discuss.php?d=445065
https://bugzilla.redhat.com/show_bug.cgi?id=2179422
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3QZN34VSF4HTCW3C3ZP2OZYSLYUKADPF/
https://moodle.org/mod/forum/discuss.php?d=445065

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