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The attack vector of a malicious SVG-file is when it is displayed in the survey. It's about the backend and how many different survey administrators are on the server doing things.So uploading an SVG logo for in the theme might be possible, while uploading SVG via a file upload question might be made impossible.
// Please be very careful if you want to allow SVG files - there are several XSS dangerous security issues$config['allowedthemeimageformats'] = 'gif,ico,jpg,png'; // Image file types allowed to be uploaded in the themes section.$config['allowedthemeuploads'] = 'css,js,map,json,eot,otf,ttf,woff,txt,md,xml,woff2,twig'; // Other file types allowed to be uploaded in the themes section.$config['allowedfileuploads'] = [//Documents'xls', 'doc', 'xlsx', 'docx', 'odt', 'ods', 'pdf',//Images - as mentioned above be very careful if you want to allow SVG files'png', 'bmp', 'gif', 'jpg', 'jpeg', 'tif',// Iphone file extensions (version 11 and above)'heif', 'heic', 'heifs', 'heics', 'avci', 'avcs', 'avif', 'avifs',//soundfiles'wav', 'mp3', 'flac', 'aac', 'm4a', 'opus', 'ogg', 'wma', 'mka',//videos'mp4', 'avi', 'mkv', 'mpeg', 'mpg', 'wmv', 'h264', 'h265', 'mov', 'webm', 'divx', 'xvid',];// NB: Allowing XML enables XSS, since XML can be an HTML page.$config['allowedresourcesuploads'] = '7z,aiff,asf,avi,bmp,csv,doc,docx,fla,flv,gif,gz,gzip,ico,jpeg,jpg,mid,mov,mp3,mp4,mpc,mpeg,mpg,ods,odt,pdf,png,ppt,pxd,qt,ram,rar,rm,rmi,rmvb,rtf,sdc,sitd,swf,sxc,sxw,tar,tgz,tif,tiff,txt,vsd,wav,wma,wmv,xls,xlsx,zip,css,js'; // File types allowed to be uploaded in the resources sections, and with the HTML Editor$config['allowedpluginuploads'] = 'gif,ico,jpg,png,css,js,map,json,eot,otf,ttf,woff,txt,md,xml,woff2,twig,php,html';