The plugin enables authenticated users with "aioseo_tools_settings" privilege (most of the time admin) to execute arbitrary code on the underlying host. Users can restore plugin's configuration by uploading a backup .ini file in the section "Tool > Import/Export". However, the plugin attempts to unserialize values of the .ini file. Moreover, the plugin embeds Monolog library which can be used to craft a gadget chain and thus trigger system command execution. As exploitation requires high privileges, the main threat scenario concerns attackers willing to compromise system host on mutualized wordpress platform where plugin installation has been denied by security hardening by hosting provider (DISALLOW_FILE_MODS=true in config).
WordPress All In One SEO Pack plugin <= 18.104.22.168 - Authenticated Remote Code Execution (RCE) vulnerability