Craft is a flexible, user-friendly CMS for creating custom digital experiences on the web and beyond. Users of affected versions are affected by this vulnerability if their php.ini configuration has `register_argc_argv` enabled. For these users an unspecified remote code execution vector is present. Users are advised to update to version 3.9.14, 4.13.2, or 5.5.2. Users unable to upgrade should disable `register_argc_argv` to mitigate the issue.