CVE-2021-27131: moodle Cross-site Scripting

Vulnerability summary

CVE-2021-27131 is a medium (CVSS 5.4) Cross-site Scripting vulnerability in moodle. EPSS estimates a 0.69% chance of exploitation in the next 30 days, higher than 52% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 16-05-2023
   PublishedVulnerability first disclosed.
2. 03-08-2024
   Last modifiedVulnerability information updated.

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).

• CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.