CVE-2023-39962: Nextcloud Server

High severity, CVSS 7.7. EPSS: 1% chance of exploitation in the next 30 days.

Nextcloud Server provides data storage for Nextcloud, an open source cloud platform. Starting in version 19.0.0 and prior to versions 19.0.13.10, 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.8, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1, a malicious user could delete any personal or global external storage, making them inaccessible for everyone else as well. Nextcloud server versions 25.0.9, 26.0.4, and 27.0.1 and Nextcloud Enterprise Server versions 19.0.13.10, 20.0.14.15, 21.0.9.13, 22.2.10.14, 23.0.12.9, 24.0.12.5, 25.0.9, 26.0.4, and 27.0.1 contain a patch for this issue. As a workaround, disable app files_external. This also makes the external storage inaccessible but retains the configurations until a patched version has been deployed.

Affected products

• Nextcloud Nextcloud Server: from 19.0.0, before 19.0.13.10 (fixed in 19.0.13.10); from 20.0.0, before 20.0.14.15 (fixed in 20.0.14.15); from 21.0.0, before 21.0.9.13 (fixed in 21.0.9.13); from 22.0.0, before 22.2.10.14 (fixed in 22.2.10.14); from 23.0.0, before 23.0.12.9 (fixed in 23.0.12.9); from 24.0.0, before 24.0.12.5 (fixed in 24.0.12.5); …

Published 2023-08-10. Last modified 2026-06-17.