MaxSite CMS through 109.6 passes the cisession cookie to unserialize() without class restrictions, allowing unauthenticated attackers to inject PHP objects. Attackers can forge valid session cookies using the hardcoded encryption key to trigger magic methods and corrupt application state or achieve code execution if gadget classes exist.

MaxSite CMS contains a PHP object injection vulnerability that allows unauthenticated attackers to execute arbitrary code by passing attacker-controlled serialized data in the maxsitecomuser cookie directly to unserialize() without validation or class allowlisting. Attackers can craft a malicious serialized PHP object payload delivered in a single HTTP request to trigger magic methods during object graph reconstruction, enabling property-oriented programming attacks or remote code execution via available gadget chains such as those targeting SoapClient or Imagick extensions.

Cross Site Scripting vulnerability in MaxSite CMS v.109.2 allows a remote attacker to obtain sensitive information via the Backend page file upload endpoint used by adminpage

A vulnerability was found in MaxSite CMS up to 109.3. Impacted is an unknown function of the component ushki Plugin. Performing a manipulation of the argument fushkanew/fushk results in cross site scripting. Remote exploitation of the attack is possible. The exploit has been made public and could be used. Upgrading to version 109.4 is recommended to address this issue. The patch is named 8a3946bd0a54bfb72a4d57179fcd253f2c550cd7. Upgrading the affected component is recommended. The vendor was informed early about this issue. They classify it as a "Self-XSS". They deployed a countermeasure: "Nevertheless, we consider this a violation of secure coding standards. The lack of filtering via htmlspecialchars() has already been fixed in the latest patch to prevent incorrect data display."

A weakness has been identified in MaxSite CMS up to 109.3. Affected by this vulnerability is an unknown functionality of the file /admin/pluginantispam of the component Antispam Plugin. Executing a manipulation of the argument floggingfile can lead to cross site scripting. It is possible to launch the attack remotely. The exploit has been made available to the public and could be used for attacks. Upgrading to version 109.4 addresses this issue. This patch is called 8a3946bd0a54bfb72a4d57179fcd253f2c550cd7. Upgrading the affected component is advised. The vendor was informed early about this issue. They classify it as a "Self-XSS". They deployed a countermeasure: "Nevertheless, we consider this a violation of secure coding standards. The lack of filtering via htmlspecialchars() has already been fixed in the latest patch to prevent incorrect data display."