CVE-2021-20280 : What You Need to Know

This CVE-2021-20280 affects Moodle versions before 3.10.2, 3.9.5, 3.8.8, 3.5.17. It involves text-based feedback answers that needed additional sanitizing to prevent stored XSS and blind SSRF risks.

Understanding CVE-2021-20280

This section provides insights into the impact, technical details, and mitigation strategies related to CVE-2021-20280.

What is CVE-2021-20280?

The vulnerability in Moodle versions prior to 3.10.2, 3.9.5, 3.8.8, 3.5.17 arises from insufficient sanitization of text-based feedback answers, leading to potential stored XSS and blind SSRF risks.

The Impact of CVE-2021-20280

The security flaw allows attackers to execute stored cross-site scripting (XSS) attacks and blind Server-Side Request Forgery (SSRF) risks, compromising the integrity and confidentiality of Moodle installations.

Technical Details of CVE-2021-20280

Explore specific technical aspects of the vulnerability to gain a clearer understanding.

Vulnerability Description

Due to inadequate sanitization of text-based feedback answers, Moodle installations before versions 3.10.2, 3.9.5, 3.8.8, 3.5.17 are exposed to stored XSS and blind SSRF vulnerabilities.

Affected Systems and Versions

Moodle versions earlier than 3.10.2, 3.9.5, 3.8.8, 3.5.17 are impacted by this vulnerability. Users of these versions are at risk of exploitation if not promptly addressed.

Exploitation Mechanism

Attackers can weaponize the vulnerability by injecting malicious scripts or URLs into feedback answers, enabling them to execute XSS attacks or trigger SSRF actions.

Mitigation and Prevention

Protect your systems by following these crucial steps to mitigate the risks posed by CVE-2021-20280.

Immediate Steps to Take

Update Moodle to versions 3.10.2, 3.9.5, 3.8.8, 3.5.17 to fix the vulnerability.
Educate users about safe usage practices to prevent exploitation of XSS and SSRF risks.

Long-Term Security Practices

Regularly update Moodle and other software to ensure vulnerabilities are promptly addressed.
Implement content security policies (CSPs) to control script execution and prevent malicious actions.

Patching and Updates

Stay informed about security advisories and patches released by Moodle to stay protected against emerging threats.