A flaw was found in Moodle versions 3.6 to 3.6.1, 3.5 to 3.5.3, 3.4 to 3.4.6, 3.1 to 3.1.15 and earlier unsupported versions. The 'manage groups' capability did not have the 'XSS risk' flag assigned to it, but does have that access in certain places. Note that the capability is intended for use by trusted users, and is only assigned to teachers and managers by default.

Cross-site scripting (XSS) vulnerability in io.swf in the IO Utility component in Yahoo! YUI 3.0.0 through 3.9.1, as used in Moodle through 2.1.10, 2.2.x before 2.2.11, 2.3.x before 2.3.8, 2.4.x before 2.4.5, 2.5.x before 2.5.1, and other products, allows remote attackers to inject arbitrary web script or HTML via a crafted string in a URL.

Cross-site scripting (XSS) vulnerability in io.swf in the IO Utility component in Yahoo! YUI 3.10.2, as used in Moodle through 2.1.10, 2.2.x before 2.2.11, 2.3.x before 2.3.8, 2.4.x before 2.4.5, 2.5.x before 2.5.1, and other products, allows remote attackers to inject arbitrary web script or HTML via a crafted string in a URL. NOTE: this vulnerability exists because of a CVE-2013-4939 regression.

Cross-site scripting (XSS) vulnerability in flashuploader.swf in the Uploader component in Yahoo! YUI 3.5.0 through 3.9.1, as used in Moodle through 2.1.10, 2.2.x before 2.2.11, 2.3.x before 2.3.8, 2.4.x before 2.4.5, 2.5.x before 2.5.1, and other products, allows remote attackers to inject arbitrary web script or HTML via a crafted string in a URL.

Cross-site scripting (XSS) vulnerability in uploader.swf in the Uploader component in Yahoo! YUI 3.2.0 through 3.9.1, as used in Moodle through 2.1.10, 2.2.x before 2.2.11, 2.3.x before 2.3.8, 2.4.x before 2.4.5, 2.5.x before 2.5.1, and other products, allows remote attackers to inject arbitrary web script or HTML via a crafted string in a URL.