admin/roles/override.php in Moodle 2.0.x before 2.0.9, 2.1.x before 2.1.6, and 2.2.x before 2.2.3 allows remote authenticated users to gain privileges by leveraging the teacher role and modifying their own capabilities, as demonstrated by obtaining the backup:userinfo capability.

class.phpmailer.php in the PHPMailer library, as used 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 and other products, allows remote authenticated users to inject arbitrary e-mail headers via vectors involving a crafted (1) From: or (2) Sender: header.

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.

The form-autocompletion functionality in Moodle 2.0.x before 2.0.7, 2.1.x before 2.1.4, and 2.2.x before 2.2.1 makes it easier for physically proximate attackers to discover passwords by reading the contents of a non-password field, as demonstrated by accessing a create-groups page with Safari on an iPad device.

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.

Moodle 2.0.x before 2.0.7 and 2.1.x before 2.1.4, when an anonymous front-page forum is enabled, allows remote attackers to obtain session keys for their sessions by visiting the front page.