CVE-2021-40691 Moodle Improper Authentication

Medium 4.3 Published 21 Jan 2022 Updated 4 Aug 2024

Attackers can hijack sessions in Moodle's Shibboleth authentication plugin, potentially taking over user accounts.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: Available

What is CVE-2021-40691?

CVE-2021-40691 is a medium-severity authentication bypass vulnerability in Moodle Moodle, published on 21 Jan 2022. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

A session hijack risk was identified in the Shibboleth authentication plugin.

Which versions are affected by CVE-2021-40691?

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

Package	Affected	Fixed in
`moodle/moodle` Packagist	From `3.10`	`3.10.7`
`moodle/moodle` Packagist	From `3.10`	`3.10.7`
`moodle/moodle` Packagist	From `3.11`	`3.11.3`
`moodle/moodle` Packagist	From `3.11`	`3.11.3`
`moodle/moodle` Packagist	From `3.9`	`3.9.10`
`moodle/moodle` Packagist	From `3.9`	`3.9.10`

1 more packages

moodle Bitnami All versions 3.9.10, 3.10.7, 3.11.3

Products include Moodle Moodle.

How do I fix CVE-2021-40691?

Upgrade moodle/moodle to a fixed version for your release line: 3.10.7, 3.11.3 or 3.9.10.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2021-40691 being exploited?

There is no known exploitation of CVE-2021-40691 in the wild and no public exploit code.

All Moodle Moodle vulnerabilities

Sources

Also known as BIT-moodle-2021-40691, GHSA-92vh-mr2w-j2cr, UBUNTU-CVE-2021-40691.