{"id":"CVE-2021-32728","aliases":["DEBIAN-CVE-2021-32728","DSA-4974-1","EUVD-2021-19510","GHSA-f5fr-5gcv-6cc5","MGASA-2021-0421","UBUNTU-CVE-2021-32728"],"status":"published","title":"End-to-end encryption device setup did not verify public key","description":"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.","severity":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00851,"percentile":0.58696,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-295"],"published":"2021-08-18T16:00:13Z","modified":"2026-10-23T18:03:38Z","fixes":[{"ecosystem":"Debian:12","package":"nextcloud-desktop","fixed_in":["3.3.1-1"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"nextcloud-desktop","fixed_in":["3.3.1-1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"nextcloud-desktop","fixed_in":["3.3.1-1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"nextcloud-desktop","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.3.1-1"}]}]},{"source":"osv","ecosystem":"Debian:13","package":"nextcloud-desktop","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.3.1-1"}]}]},{"source":"osv","ecosystem":"Debian:14","package":"nextcloud-desktop","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.3.1-1"}]}]},{"source":"osv","ecosystem":"Debian:10","package":"nextcloud-desktop","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.5.1-3+deb10u2"}]}],"versions":["2.5.1-3","2.5.1-3+deb10u1"],"bundled":2},{"source":"osv","ecosystem":"Debian:11","package":"nextcloud-desktop","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.1.1-2+deb11u1"}]}],"versions":["3.1.1-2"],"bundled":2},{"source":"osv","ecosystem":"Mageia:8","package":"nextcloud-client","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.3.3-1.mga8"}]}],"bundled":2},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"nextcloud-desktop","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.5.3-1","2.6.0-1","2.6.1-1","2.6.1-2","2.6.2-1","2.6.2-1build1"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"nextcloud-desktop","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.2.3-0ubuntu1","3.3.5-1","3.3.5-1ubuntu1","3.4.2-1","3.4.2-1ubuntu1"]}],"products":[{"vendor":"debian","product":"debian_linux"},{"vendor":"kiteworks","product":"security-advisories"},{"vendor":"nextcloud","product":"desktop"},{"vendor":"nextcloud","product":"security-advisories"}],"references":[{"url":"https://hackerone.com/reports/1189162","tags":["x_refsource_MISC","x_transferred","Exploit","Third Party Advisory","evidence","report"]},{"url":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-f5fr-5gcv-6cc5","tags":["x_refsource_CONFIRM","x_transferred","Exploit","Third Party Advisory","evidence","report"]},{"url":"https://github.com/nextcloud/desktop/pull/3338","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","report"]},{"url":"https://www.debian.org/security/2021/dsa-4974","tags":["vendor-advisory","x_refsource_DEBIAN","x_transferred","Third Party Advisory","advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2021-32728","tags":["advisory"]},{"url":"https://advisories.mageia.org/MGASA-2021-0421.html","tags":["advisory"]},{"url":"https://bugs.mageia.org/show_bug.cgi?id=29043","tags":["report"]},{"url":"https://security-tracker.debian.org/tracker/source-package/nextcloud-desktop","tags":["web"]},{"url":"https://ubuntu.com/security/CVE-2021-32728","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-32728","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2021-32728","title":"End-to-end encryption device setup did not verify public key","description":"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.","status":"published","published":"2021-08-18T16:00:13Z","modified":"2024-08-03T23:33:54.918Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/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-2021-19510","description":"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.","status":"published","published":"2021-08-18T16:00:13Z","modified":"2024-08-03T23:33:54Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-03T03:24:35.855495Z"}],"nvd":[{"id":"CVE-2021-32728","description":"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.","status":"published","published":"2021-08-18T16:15:07.293Z","modified":"2026-06-17T03:53:30.743Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"primary"},{"version":"2.0","score":4,"vector":"AV:N/AC:L/Au:S/C:P/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-295"],"updated_at":"2026-11-02T14:06:57.318236Z"}],"osv":[{"id":"CVE-2021-32728","description":"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.","status":"published","published":"2021-08-18T16:15:07.293Z","modified":"2026-10-20T10:54:42.653408768Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T15:44:19.793849Z"},{"id":"DEBIAN-CVE-2021-32728","description":"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.","status":"published","published":"2021-08-18T16:15:07.293Z","modified":"2026-10-23T18:03:38.272282257Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T15:45:35.233346Z"},{"id":"UBUNTU-CVE-2021-32728","description":"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.","status":"published","published":"2021-08-18T16:15:00Z","modified":"2026-04-22T12:54:23.146922Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T15:54:27.332852Z"},{"id":"DSA-4974-1","title":"nextcloud-desktop - security update","status":"published","published":"2021-09-19T00:00:00Z","modified":"2026-03-09T02:11:45.153707Z","updated_at":"2026-11-02T15:46:17.19998Z"},{"id":"MGASA-2021-0421","title":"Updated nextcloud-client packages fix security vulnerability","description":"Nextcloud Desktop Client before 3.3.1 is vulnerable to improper certificate\nvalidation due to lack of SSL certificate verification when using the\n\"Register with a Provider\" flow. (CVE-2021-22895)\n\nIn versions prior to 3.3.0, the Nextcloud Desktop client fails to check if\na private key belongs to previously downloaded public certificate. If the\nNextcloud instance serves a malicious public key, the data would be\nencrypted for this key and thus could be accessible to a malicious actor.\nThis issue is fixed in Nextcloud Desktop Client version 3.3.0\n","status":"published","published":"2021-09-23T04:49:29Z","modified":"2026-04-16T04:44:45.283905187Z","updated_at":"2026-11-02T15:49:41.849028Z"}]}}