What’s Vulnerable › Vulnerabilities

CVE-2023-28332: Moodle: algebra filter xss when filter is misconfigured

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% 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-79

Description

If the algebra filter was enabled but not functional (eg the necessary binaries were missing from the server), it presented an XSS risk.

Affected products

• 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=2179419
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3QZN34VSF4HTCW3C3ZP2OZYSLYUKADPF/
• https://moodle.org/mod/forum/discuss.php?d=445064
• https://bugzilla.redhat.com/show_bug.cgi?id=2179419
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3QZN34VSF4HTCW3C3ZP2OZYSLYUKADPF/
• https://moodle.org/mod/forum/discuss.php?d=445064

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