Description
The error-message functionality in Moodle 1.9.x before 1.9.13, 2.0.x before 2.0.4, and 2.1.x before 2.1.1 does not ensure that a continuation link refers to an http or https URL for the local Moodle instance, which might allow attackers to trick users into visiting arbitrary web sites via unspecified vectors.
Remediation
References
Related Vulnerabilities
Drupal URL Redirection to Untrusted Site ('Open Redirect') Vulnerability (CVE-2020-13662)
WordPress Permissions, Privileges, and Access Controls Vulnerability (CVE-2012-3383)
MySQL Other Vulnerability (CVE-2010-3838)
PHP Improper Link Resolution Before File Access ('Link Following') Vulnerability (CVE-2014-3981)