CVE-2023-28833: Nextcloud Server

High severity, CVSS 8.8. EPSS: 0.8% chance of exploitation in the next 30 days.

Nextcloud server is an open source home cloud implementation. In affected versions admins of a server were able to upload a logo or a favicon and to provided a file name which was not restricted and could overwrite files in the appdata directory. Administrators may have access to overwrite these files by other means but this method could be exploited by tricking an admin into uploading a maliciously named file. It is recommended that the Nextcloud Server is upgraded to 24.0.10 or 25.0.4. Users unable to upgrade should avoid ingesting logo files from untrusted sources.

Affected products

• Nextcloud Nextcloud Server: from 23.0.0, before 23.0.14 (fixed in 23.0.14); from 24.0.0, before 24.0.10 (fixed in 24.0.10); from 25.0.0, before 25.0.4 (fixed in 25.0.4)

Published 2023-03-30. Last modified 2026-06-17.