WonderCMS Theme Installation/Plugin Installation installUpdateModuleAction unrestricted upload

A vulnerability, which was classified as critical, has been found in WonderCMS 3.5.0. Affected by this issue is the function installUpdateModuleAction of the component Theme Installation/Plugin Installation. The manipulation leads to unrestricted upload. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. The real existence of this vulnerability is still doubted at the moment. The vendor explains, that "[t]he philosophy has always been, admin [...] bear responsibility to not install themes/plugins from untrusted sources."