CVE-2021-36401 Moodle vulnerable to Stored Cross-site Scripting

What is CVE-2021-36401?

CVE-2021-36401 is a medium-severity cross-site scripting vulnerability in Moodle Moodle, published on 6 Mar 2023. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

Official description

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

Weakness: CWE-79

Which versions are affected by CVE-2021-36401?

7 open source packages ship an affected version, including moodle/moodle and moodle. It affects 1 product.

Products include Moodle Moodle.

How do I fix CVE-2021-36401?

Upgrade moodle/moodle to a fixed version for your release line: 3.9.8, 3.10.5 or 3.11.1.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2021-36401 being exploited?

There is no known exploitation of CVE-2021-36401 in the wild and no public exploit code.

Other vulnerabilities in Moodle Moodle

• CVE-2006-4935 File upload in n/a Critical 10.0
• CVE-2006-4936 Moodle does not properly validate module instance id Critical 10.0
• CVE-2004-2233 Unknown "front page vulnerability with Moodle servers" for Moodle before 1.3.2 has unknown impact and attack vectors. Critical 10.0
• CVE-2004-2235 Cross-site scripting in n/a Critical 10.0
• CVE-2004-2236 Other in n/a Critical 10.0

All Moodle Moodle vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BIT-moodle-2021-36401, GHSA-g6h6-4fp6-w33w, UBUNTU-CVE-2021-36401.