In Opencast before 7.6 and 8.1, using a remember-me cookie with an arbitrary username can cause Opencast to assume proper authentication for that user even if the remember-me cookie was incorrect given that the attacked endpoint also allows anonymous access. This way, an attacker can, for example, fake a remember-me token, assume the identity of the global system administrator and request non-public content from the search service without ever providing any proper authentication. This problem is fixed in Opencast 7.6 and Opencast 8.1

Opencast before 8.1 and 7.6 allows almost arbitrary identifiers for media packages and elements to be used. This can be problematic for operation and security since such identifiers are sometimes used for file system operations which may lead to an attacker being able to escape working directories and write files to other locations. In addition, Opencast's Id.toString(…) vs Id.compact(…) behavior, the latter trying to mitigate some of the file system problems, can cause errors due to identifier mismatch since an identifier may unintentionally change. This issue is fixed in Opencast 7.6 and 8.1.

Opencast before 7.6 and 8.1 enables a remember-me cookie based on a hash created from the username, password, and an additional system key. This means that an attacker getting access to a remember-me token for one server can get access to all servers which allow log-in using the same credentials without ever needing the credentials. This problem is fixed in Opencast 7.6 and Opencast 8.1

Opencast before 8.1 and 7.6 allows unauthorized public access to all media and metadata by default via OAI-PMH. OAI-PMH is part of the default workflow and is activated by default, requiring active user intervention of users to protect media. This leads to users unknowingly handing out public access to events without their knowledge. The problem has been addressed in Opencast 7.6 and 8.1 where the OAI-PMH endpoint is configured to require users with `ROLE_ADMIN` by default. In addition to this, Opencast 9 removes the OAI-PMH publication from the default workflow, making the publication a conscious decision users have to make by updating their workflows.

Opencast before 8.1 stores passwords using the rather outdated and cryptographically insecure MD5 hash algorithm. Furthermore, the hashes are salted using the username instead of a random salt, causing hashes for users with the same username and password to collide which is problematic especially for popular users like the default `admin` user. This essentially means that for an attacker, it might be feasible to reconstruct a user's password given access to these hashes. Note that attackers needing access to the hashes means that they must gain access to the database in which these are stored first to be able to start cracking the passwords. The problem is addressed in Opencast 8.1 which now uses the modern and much stronger bcrypt password hashing algorithm for storing passwords. Note, that old hashes remain MD5 until the password is updated. For a list of users whose password hashes are stored using MD5, take a look at the `/user-utils/users/md5.json` REST endpoint.

Opencast 2.3.2 and older versions are vulnerable to script injections through media and metadata in the player and media module resulting in arbitrary code execution, fixed in 2.3.3 and 3.0.

In Opencast 2.2.3 and older if user names overlap, the Opencast search service used for publication to the media modules and players will handle the access control incorrectly so that users only need to match part of the user name used for the access restriction. For example, a user with the role ROLE_USER will have access to recordings published only for ROLE_USER_X.