Ametys before 4.0.3 requires authentication only for URIs containing a /cms/ substring, which allows remote attackers to bypass intended access restrictions via a direct request to /plugins/core-ui/servercomm/messages.xml, as demonstrated by changing the admin password by obtaining account details via a users/search.json request, and then modifying the account via an editUser request.

The auto-completion plugin in Ametys CMS before 4.5.0 allows a remote unauthenticated attacker to read documents such as plugins/web/service/search/auto-completion/<domain>/en.xml (and similar pathnames for other languages), which contain all characters typed by all users, including the content of private pages. For example, a private page may contain usernames, e-mail addresses, and possibly passwords.

Ametys CMS v4.4.1 contains a persistent cross-site scripting vulnerability in the link directory's input fields for external links. Attackers can inject malicious script code in link text and descriptions to execute persistent attacks that compromise user sessions and manipulate application modules.