A stored web content injection vulnerability (WCI, a.k.a XSS) is present in MODX Revolution CMS version 2.5.6 and earlier. An authenticated user with permissions to edit users can save malicious JavaScript as a User Group name and potentially take control over victims' accounts. This can lead to an escalation of privileges providing complete administrative control over the CMS.

Cross-site scripting (XSS) vulnerability in login-fsp.html in MODX Revolution before 1.9.1 allows remote attackers to inject arbitrary web script or HTML via the QUERY_STRING.

In MODX Revolution 2.5.7, the "key" and "name" parameters in the System Settings module are vulnerable to XSS. A malicious payload sent to connectors/index.php will be triggered by every user, when they visit this module.

In MODX Revolution before 2.5.7, a user with resource edit permissions can inject an XSS payload into the title of any post via the pagetitle parameter to connectors/index.php.

In MODX Revolution before 2.5.7, an attacker might be able to trigger XSS by injecting a payload into the HTTP Host header of a request. This is exploitable only in conjunction with other issues such as Cache Poisoning.

In MODX Revolution before 2.5.7, an attacker is able to trigger Reflected XSS by injecting payloads into several fields on the setup page, as demonstrated by the database_type parameter.

In MODX Revolution before 2.5.7, a user with file upload permissions is able to execute arbitrary code by uploading a file with the name .htaccess.

In MODX Revolution before 2.5.7, when PHP 5.3.3 is used, an attacker is able to include and execute arbitrary files on the web server due to insufficient validation of the action parameter to setup/index.php, aka directory traversal.

Directory traversal in setup/processors/url_search.php (aka the search page of an unused processor) in MODX Revolution 2.5.7 might allow remote attackers to obtain system directory information.

The (1) update and (2) package-installation features in MODX Revolution 2.5.4-pl and earlier use http://rest.modx.com by default, which allows man-in-the-middle attackers to spoof servers and trigger the execution of arbitrary code by leveraging the lack of the HTTPS protection mechanism.