CVE-2021-39223

Nextcloud is an open-source, self-hosted productivity platform. The Nextcloud Richdocuments application prior to versions 3.8.6 and 4.2.3 returned verbatim exception messages to the user. This could result in a full path disclosure on shared files. (e.g. an attacker could see that the file shared.txt is located within /files/$username/Myfolder/Mysubfolder/shared.txt). It is recommended that the Richdocuments application is upgraded to 3.8.6 or 4.2.3. As a workaround, disable the Richdocuments application in the app settings.