{"id":"BIT-nextcloud-2021-32727","summary":"End-to-end encryption device setup did not verify public key","details":"Nextcloud Android Client is the Android client for Nextcloud. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.16.1, the Nextcloud Android client skipped a step that involved the client checking if a private key belonged to a previously downloaded public certificate. If the Nextcloud instance served a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. The vulnerability is patched in version 3.16.1. As a workaround, do not add additional end-to-end encrypted devices to a user account.","aliases":["CVE-2021-32727","GHSA-5v33-r9cm-7736"],"modified":"2026-09-08T08:48:16.234192843Z","published":"2026-07-12T23:47:43.538Z","database_specific":{"cpes":["cpe:2.3:a:nextcloud:nextcloud:*:*:*:*:*:android:*:*"],"severity":"High"},"references":[{"type":"ADVISORY","url":"https://github.com/nextcloud/android/pull/8438"},{"type":"ADVISORY","url":"https://github.com/nextcloud/end_to_end_encryption_rfc/blob/7f002996397faefb664019a97ebb0a1e210f64f0/RFC.md#further-devices"},{"type":"ADVISORY","url":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736"},{"type":"WEB","url":"https://hackerone.com/reports/1189162"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-32727"}],"affected":[{"package":{"name":"nextcloud","ecosystem":"Bitnami","purl":"pkg:bitnami/nextcloud"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.16.1"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/nextcloud/BIT-nextcloud-2021-32727.json"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"}]}],"schema_version":"1.9.0"}