{"id":"CVE-2021-32727","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-32727","generatedAt":"2026-10-27T21:20:33.456Z","title":"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.","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.","published":"2021-07-12T21:15:08.000Z","lastModified":"2026-06-17T03:53:31.000Z","status":"Modified","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"},"cwe":["CWE-295"],"affected":["nextcloud/nextcloud"],"epss":{"score":0.00732,"percentile":0.54053,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.73%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://github.com/nextcloud/android/pull/8438","tags":["Third Party Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/nextcloud/end_to_end_encryption_rfc/blob/7f002996397faefb664019a97ebb0a1e210f64f0/RFC.md#further-devices","tags":["Third Party Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736","tags":["Third Party Advisory"],"source":"security-advisories@github.com"},{"url":"https://hackerone.com/reports/1189162","tags":["Permissions Required"],"source":"security-advisories@github.com"},{"url":"https://github.com/nextcloud/android/pull/8438","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/nextcloud/end_to_end_encryption_rfc/blob/7f002996397faefb664019a97ebb0a1e210f64f0/RFC.md#further-devices","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/nextcloud/security-advisories/security/advisories/GHSA-5v33-r9cm-7736","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://hackerone.com/reports/1189162","tags":["Permissions Required"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-32727","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}