The rc4encrypt function in lib/moodlelib.php in Moodle 1.9.x before 1.9.16, 2.0.x before 2.0.7, 2.1.x before 2.1.4, and 2.2.x before 2.2.1 uses a hardcoded password of nfgjeingjk, which makes it easier for remote attackers to defeat cryptographic protection mechanisms by reading this script's source code within the open-source software distribution.

Moodle 1.9.x before 1.9.16, 2.0.x before 2.0.7, 2.1.x before 2.1.4, and 2.2.x before 2.2.1 allows remote attackers to view the profile images of arbitrary user accounts via unspecified vectors.

Moodle 1.9.x before 1.9.16, 2.0.x before 2.0.7, 2.1.x before 2.1.4, and 2.2.x before 2.2.1 does not validate e-mail address settings, which allows remote authenticated users to have an unspecified impact via a crafted address.

mod/forum/user.php in Moodle 1.9.x before 1.9.16 allows remote authenticated users to obtain the names and other details of arbitrary user accounts by searching for posts.

Multiple cross-site scripting (XSS) vulnerabilities in lib/weblib.php in Moodle 1.9.x before 1.9.12 allow remote attackers to inject arbitrary web script or HTML via vectors related to URL encoding.

Moodle 1.9.x before 1.9.12 and 2.0.x before 2.0.3 does not properly implement associations between teachers and groups, which allows remote authenticated users to read quiz reports of arbitrary students by leveraging the teacher role.

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.

mod/forum/user.php in Moodle 1.9.x before 1.9.14, 2.0.x before 2.0.5, and 2.1.x before 2.1.2 allows remote authenticated users to discover the names of other users via unspecified vectors.

The MoodleQuickForm class in the Forms Library in lib/formslib.php in Moodle 1.9.x before 1.9.14, 2.0.x before 2.0.5, and 2.1.x before 2.1.2 does not recognize Forms API setConstant operations, which allows remote attackers to submit unexpected form content by modifying the values of constant fields.

message/refresh.php in Moodle 1.9.x before 1.9.14 allows remote authenticated users to cause a denial of service (infinite request loop) via a URL that specifies a zero wait time for message refreshing.