What’s Vulnerable › Vulnerabilities

CVE-2021-36401

• Severity: medium (CVSS 4.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2023-03-06 · updated 2026-06-17
• Weakness: CWE-79

Description

In Moodle, ID numbers exported in HTML data formats required additional sanitizing to prevent a local stored XSS risk.

Affected products

• Moodle: before 3.9.8; from 3.10.0 before 3.10.5; from 3.11.0 before 3.11.1 — fixed in 3.10.5, 3.11.1, 3.9.8

How to fix

Upgrade to a fixed version: Moodle 3.10.5, 3.11.1, 3.9.8. Check the vendor advisory for mitigations.

References

• https://moodle.org/mod/forum/discuss.php?d=424807
• https://moodle.org/mod/forum/discuss.php?d=424807

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