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TI-2021-12395 Aliases CVE-2021-32727

End-to-end encryption device setup did not verify public key

Priority LOW 34CWE-295Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Spoofing
Confidentiality · integrity · availability
High · None · None
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-295.

Summary

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.

Why it matters now

EPSS 0.00732 54th percentileScored 2026-11-07
Fix Fixed security-advisories (nextcloud): 3.16.1

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
nextcloudsecurity-advisoriesbefore 3.16.13.16.1Patch availableCNA
  • security-advisories Vendornextcloud Affected before 3.16.1 Fixed in 3.16.1 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nextcloud:nextcloud:*:*:*:*:*:android:*:*before 3.16.1Vulnerablenextcloud
  • cpe:2.3:a:nextcloud:nextcloud:*:*:*:*:*:android:*:* Versions before 3.16.1 Vulnerable ·nextcloud

Remediation

  • Fix · CNA security-advisories (nextcloud) Fixed in 3.16.1

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-32727

References

Advisory 3

Other 1

  • TI-2022-11704 Sensitive files/data exist after deletion of user account in Nextcloud Android CVSS 3.1LOW 3.3
  • TI-2022-08695 Improper Authentication in Nextcloud Android Files CVSS 3.1LOW 2.4
  • TI-2019-03862 SQL injection in com.nextcloud.client CVSS 3.1CRITICAL 9.8
  • TI-2021-19669 SQL Injection in FileContentProvider (GHSL-2021-1007) CVSS 3.1HIGH 7.5
  • TI-2023-13460 Nextcloud: Lack of authenticity of metadata keys allows a malicious server to gain access to E2EE folders CVSS 3.1MEDIUM 6.9
  • TI-2021-05773 Information disclosure in Nextcloud iOS app CVSS 3.1MEDIUM 6.5
See all 27 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences