An improper neutralization of input during web page generation ('Cross-site Scripting') vulnerability in Theme API in Synology DiskStation Manager (DSM) before 7.2.1-69057-12, 7.2.2-72806-9, 7.3.2-86009-4 and 7.4-90075 allows remote authenticated users with administrator privileges to read or write limited files.
https://www.synology.com/en-global/security/advisory/Synology_SA_26_13