filter/urltolink/filter.php in Moodle through 2.5.9, 2.6.x before 2.6.9, 2.7.x before 2.7.6, and 2.8.x before 2.8.4 allows remote authenticated users to cause a denial of service (CPU consumption or partial outage) via a crafted string that is matched against an improper regular expression.

files/externallib.php in Moodle through 2.5.9, 2.6.x before 2.6.11, 2.7.x before 2.7.8, and 2.8.x before 2.8.6 does not consider the moodle/user:manageownfiles capability before approving a private-file upload, which allows remote authenticated users to bypass intended file-management restrictions by using web services to perform uploads after this capability has been revoked.

Directory traversal vulnerability in the min_get_slash_argument function in lib/configonlylib.php in Moodle through 2.5.9, 2.6.x before 2.6.8, 2.7.x before 2.7.5, and 2.8.x before 2.8.3 allows remote authenticated users to read arbitrary files via a .. (dot dot) in the file parameter, as demonstrated by reading PHP scripts.

lib/moodlelib.php in Moodle through 2.5.9, 2.6.x before 2.6.9, 2.7.x before 2.7.6, and 2.8.x before 2.8.4, when the theme uses the blocks-regions feature, establishes the course state at an incorrect point in the login-validation process, which allows remote attackers to obtain sensitive course information via unspecified vectors.

mdeploy.php in Moodle through 2.5.9, 2.6.x before 2.6.9, 2.7.x before 2.7.6, and 2.8.x before 2.8.4 allows remote authenticated users to bypass intended access restrictions and extract archives to arbitrary directories via a crafted dataroot value.

login/token.php in Moodle through 2.5.9, 2.6.x before 2.6.9, 2.7.x before 2.7.6, and 2.8.x before 2.8.4 allows remote authenticated users to bypass a forced-password-change requirement by creating a web-services token.

Cross-site scripting (XSS) vulnerability in mod/quiz/report/statistics/statistics_question_table.php in Moodle through 2.5.9, 2.6.x before 2.6.9, 2.7.x before 2.7.6, and 2.8.x before 2.8.4 allows remote authenticated users to inject arbitrary web script or HTML by leveraging the student role for a crafted quiz response.

Multiple open redirect vulnerabilities in Moodle through 2.5.9, 2.6.x before 2.6.11, 2.7.x before 2.7.8, and 2.8.x before 2.8.6 allow remote attackers to redirect users to arbitrary web sites and conduct phishing attacks via vectors involving an error page that links to a URL from an HTTP Referer header.