{"id":"CVE-2021-32727","aliases":["BIT-nextcloud-2021-32727","EUVD-2021-19509","GHSA-5v33-r9cm-7736"],"status":"published","title":"End-to-end encryption device setup did not verify public key","description":"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.","severity":{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00732,"percentile":0.54829,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-295"],"published":"2021-07-12T20:40:13Z","modified":"2026-10-24T10:50:41Z","fixes":[{"ecosystem":"Bitnami","package":"nextcloud","fixed_in":["3.16.1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Bitnami","package":"nextcloud","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"3.16.1"}]}]}],"products":[{"vendor":"kiteworks","product":"security-advisories"},{"vendor":"nextcloud","product":"nextcloud"},{"vendor":"nextcloud","product":"security-advisories"}],"references":[{"url":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736","tags":["x_refsource_CONFIRM","x_transferred","Third Party Advisory","advisory"]},{"url":"https://github.com/nextcloud/android/pull/8438","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","advisory"]},{"url":"https://hackerone.com/reports/1189162","tags":["x_refsource_MISC","x_transferred","Permissions Required","web","report"]},{"url":"https://github.com/nextcloud/end_to_end_encryption_rfc/blob/7f002996397faefb664019a97ebb0a1e210f64f0/RFC.md#further-devices","tags":["x_refsource_MISC","x_transferred","Third Party Advisory","advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-32727","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2021-32727","title":"End-to-end encryption device setup did not verify public key","description":"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.","status":"published","published":"2021-07-12T20:40:13Z","modified":"2024-08-03T23:33:54.87Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-295"],"updated_at":"2026-11-02T14:33:07.014772Z"}],"euvd":[{"id":"EUVD-2021-19509","description":"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.","status":"published","published":"2021-07-12T20:40:13Z","modified":"2024-08-03T23:33:54Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-03T03:24:35.855495Z"}],"nvd":[{"id":"CVE-2021-32727","description":"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.","status":"published","published":"2021-07-12T21:15:07.817Z","modified":"2026-06-17T03:53:30.623Z","cvss":[{"version":"3.1","score":5.7,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:N/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"high","assessor":"primary"},{"version":"2.0","score":5,"vector":"AV:N/AC:L/Au:N/C:P/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-295"],"updated_at":"2026-11-02T14:06:55.747384Z"}],"osv":[{"id":"CVE-2021-32727","description":"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.","status":"published","published":"2021-07-12T21:15:07.817Z","modified":"2026-10-24T10:50:41.669467605Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","level":"high"}],"updated_at":"2026-11-02T15:44:19.793849Z"},{"id":"BIT-nextcloud-2021-32727","title":"End-to-end encryption device setup did not verify public key","description":"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.","status":"published","published":"2026-07-12T23:47:43.538Z","modified":"2026-09-08T08:48:16.234192843Z","updated_at":"2026-11-02T15:28:34.007508Z"}]}}