CVE-2021-32728: Debian Linux

Medium severity, CVSS 6.5. EPSS: 0.9% chance of exploitation in the next 30 days.

The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server with a computer. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.3.0, the Nextcloud Desktop client fails to check if a private key belongs to previously downloaded public certificate. If the Nextcloud instance serves a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. This issue is fixed in Nextcloud Desktop Client version 3.3.0. There are no known workarounds aside from upgrading.

Affected products

• Debian Debian Linux: version 10.0 only; version 11.0 only
• Nextcloud Desktop: before 3.3.0 (fixed in 3.3.0)

Published 2021-08-18. Last modified 2026-06-17.