CVE-2023-35927: Nextcloud Server

High severity, CVSS 8.1. EPSS: 0.8% chance of exploitation in the next 30 days.

NextCloud Server and NextCloud Enterprise Server provide file storage for Nextcloud, a self-hosted productivity platform. In NextCloud Server versions 25.0.0 until 25.0.7 and 26.0.0 until 26.0.2 and Nextcloud Enterprise Server versions 21.0.0 until 21.0.9.12, 22.0.0 until 22.2.10.12, 23.0.0 until 23.0.12.7, 24.0.0 until 24.0.12.2, 25.0.0 until 25.0.7, and 26.0.0 until 26.0.2, when two server are registered as trusted servers for each other and successfully exchanged the share secrets, the malicious server could modify or delete VCards in the system addressbook on the origin server. This would impact the available and shown information in certain places, such as the user search and avatar menu. If a manipulated user modifies their own data in the personal settings the entry is fixed again. Nextcloud Server n 25.0.7 and 26.0.2 and Nextcloud Enterprise Server 21.0.9.12, 22.2.10.12, 23.0.12.7, 24.0.12.2, 25.0.7, and 26.0.2 contain a patch for this issue. A workaround is available. Remove all trusted servers in the "Administration" > "Sharing" settings `…/index.php/settings/admin/sharing`. Afterwards, trigger a recreation of the local system addressbook with the following `occ dav:sync-system-addressbook`.

Affected products

• Nextcloud Nextcloud Server: from 16.0.0, before 19.0.13.9 (fixed in 19.0.13.9); from 20.0.0, before 20.0.14.14 (fixed in 20.0.14.14); from 21.0.0, before 21.0.9.12 (fixed in 21.0.9.12); from 22.0.0, before 22.2.10.12 (fixed in 22.2.10.12); from 23.0.0, before 23.0.12.7 (fixed in 23.0.12.7); from 24.0.0, before 24.0.12.2 (fixed in 24.0.12.2); …

Published 2023-06-23. Last modified 2026-06-17.