CVE-2021-32726: Nextcloud Server

Critical severity, CVSS 9.8. EPSS: 1.8% chance of exploitation in the next 30 days.

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.13, 20.011, and 21.0.3, webauthn tokens were not deleted after a user has been deleted. If a victim reused an earlier used username, the previous user could gain access to their account. The issue was fixed in versions 19.0.13, 20.0.11, and 21.0.3. There are no known workarounds.

Affected products

• Nextcloud Nextcloud Server: before 19.0.13 (fixed in 19.0.13); from 20.0.0, before 20.0.11 (fixed in 20.0.11); from 21.0.0, before 21.0.3 (fixed in 21.0.3)

Published 2021-07-12. Last modified 2026-06-17.