An issue in Monstra CMS v3.0.4 allows attackers to execute arbitrary web scripts or HTML via bypassing the file extension filter and uploading crafted HTML files.

Cross Site Scripting vulnerabilty in Monstra CMS 3.0.4 via the page feature in admin/index.php.

A stored cross site scripting (XSS) vulnerability in Monstra CMS version 3.0.4 allows attackers to execute arbitrary web scripts or HTML via crafted a payload entered into the "Site Name" field under the "Site Settings" module.

Monstra CMS 3.0.4 allows attackers to execute arbitrary code via a crafted payload entered into the "Snippet content" field under the "Edit Snippet" module.

Monstra CMS 3.0.4 allows an attacker, who already has administrative access to modify .chunk.php files on the Edit Chunk screen, to execute arbitrary OS commands via the Theme Module by visiting the admin/index.php?id=themes&action=edit_chunk URI. NOTE: there is no indication that the Edit Chunk feature was intended to prevent an administrator from using PHP's exec feature

plugins/box/users/users.plugin.php in Monstra CMS 3.0.4 allows Login Rate Limiting Bypass via manipulation of the login_attempts cookie.