CVE-2021-27131

Description

Moodle 3.10.1 is vulnerable to persistent/stored cross-site scripting (XSS) due to the improper input sanitization on the "Additional HTML Section" via "Header and Footer" parameter in /admin/settings.php. This vulnerability is leading an attacker to steal admin and all user account cookies by storing the malicious XSS payload in Header and Footer. NOTE: this is disputed by the vendor because the "Additional HTML Section" for "Header and Footer" can only be supplied by an administrator, who is intentionally allowed to enter unsanitized input (e.g., site-specific JavaScript).

How to fix CVE-2021-27131

To remediate CVE-2021-27131, upgrade the affected package to a fixed version below.

• —upgrade to 3.10.2 or later
• —no fix listed

Is CVE-2021-27131 being exploited?

Low — EPSS is 0.3%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• >= 3.10.1, < 3.10.2
• from 0, <= 3.10.1

CVSS scores

References (4)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2021-27131
• PATCHgithub.com/moodle/moodle
• WEBdocs.moodle.org/402/en/Risks
• WEBgithub.com/p4nk4jv/CVEs-Assigned/blob/master/Moodle-3.10.1-CVE-2021-27131.md